Today is 2.2.22 so I'm asking Where has London got two of?
That's pairs of places with the same name.
I'm using the Ordnance Survey's official list...
...which tells me London has seven matching pairs.
Let's compare and contrast.
Belmont and Belmont
Belmont(Harrow): This one's in zone 5 between Harrow and Stanmore. It earned its name in the early 18th century when the Duke of Chandos landscaped his estate by placing a summerhouse on a manmade mound and called it Bell Mount. The artificial hillock's still there, sealed inside Stanmore Golf Club and crossed by a single public footpath. A station opened in 1932 triggering substantial suburban development, centred on a brick parade called Belmont Circle where shops and traffic orbit a central shrubbery. Alas the railway was little-used and closed in 1964, hence Belmont remains off most Londoners' radar. Belmont(Sutton): This one's also in zone 5 but at the southern end of the borough of Sutton, right on the edge of the capital. A station opened here in 1865 and was called California after the local pub, which was pretty much the sole landmark at the time. The name was changed to Belmont ten years later, reputedly because the stationmaster was tired of receiving packages bound for America. Today the big local presence is the Royal Marsden Hospital, aka The London Cancer Hub, while a short shopping street climbs from the railway towards St John the Baptist's church. Battle of the Belmonts: A close match because both suburbs are peripherally nondescript, but Sutton's probably beats Harrow's by having a rail connection.
Bromley and Bromley
Bromley(Bromley): This one straddles zones 4 and 5 and is so important they named a borough after it. By the 9th century it existed as "woodland clearing where broom grows", later hosted bishops in its manor house and earned a market charter off King John. Again the railway kickstarted its suburban explosion, this time in 1858, becoming very much the Kentish commuter town of choice. With a modern population approaching 90,000 it is comfortably the largest 'place' on this list. Bromley(Tower Hamlets): This one's in zone 2 and has almost as long a history. A Benedictine nunnery called St Leonards Priory was extant by the Lea in the early 12th century and was namechecked by Chaucer in the Canterbury Tales. The area became Bromley St Leonard's and later just Bromley, which was fine before there were railways but led to the tube station being renamed Bromley-by-Bow in 1967. Its ascendance from 19th century industrial slum is not yet complete. It's also the only place in today's list to be found in inner rather than outer London. Battle of the Bromleys: South London thrashes East London, no question.
Church End and Church End
Church End(Barnet): Hundreds of places across the country could have been called Church End and dozens were, so it's unsurprising to find that two have survived within the Greater London boundary. This one's in zone 4 and is essentially the southern end of Finchley based around 13th century St Mary's church. It's mostly residential these days, the main commercial centre being up the road at Tally Ho Corner. Non-locals know Church End as Finchley Central, which yet again proves the nominative power of a well-named station. Church End(Brent): This one's in zone 3 between Harlesden and Neasden, with the intrinsic benefit of being neither. The church in question is another St Mary's, a place of pilgrimage since the 10th century and still home to a shrine with the unlikely name of Our Lady of Willesden. Step away from the churchyard and it's all a bit council estate, indeed Brent always seem to have a regeneration project on the go here. Battle of the Church Ends: Finchley's nicer but more diffuse, so Willesden wins by having a name that more people still regularly use.
Grove Park and Grove Park
Grove Park(Hounslow): This one's in zone 3 and lies within the big Thames meander at Chiswick. It's named after Grove House, a medieval manor in riverside meadows where the risk of flooding held back residential development well into the 19th century. A planned garden suburb never materialised, so Grove Park today is a mix of smart villas, interwar estate and covetous waterfront townhouses. Chiswick railway station is very much in Grove Park but was never called that, so a key opportunity to spread the name more widely was lost. Grove Park(Lewisham): This one's in zone 4 and is a substantial suburb between Mottingham and Bromley. The South Eastern Main Line used to zip straight through, there being nothing but fields, but in 1871 a station opened and was named after nearby Grove Farm. Housing spread slowly until 1926 when work started on the 44 acre Grove Park council estate, then another emerged across the line in Downham and the Quaggy valley is now significantly built up. Battle of the Grove Parks: Lewisham's is by far the better known, which is probably how Hounslow's residents prefer it.
Hayes and Hayes
Hayes(Bromley): This one's in zone 5 not far from West Wickham. It's another ex-medieval village, first mentioned in the 12th century, and remained rural until the railway snaked out in 1882. It bumps up against the higher ground of Hayes Common, spreads quietly up the road towards Bromley and boasts the kind of rising high street Reggie Perrin might have frequented. Hayes(Hillingdon): This one's on Crossrail in zone 5, one stop west of Southall. It's old, with St Mary's church having 9th century roots, and has long been threaded by the Grand Union Canal. These days its avenues sprawl between the Great West and Uxbridge Roads, with the station some way south of the original village's heart. That'll be why Hayes is now best known with "and Harlington" on the end, but it's much bigger than that appendage suggests. Battle of the Hayeses: Both are large, but Hillingdon's density gives it a clear edge over Bromley's.
Plaistow and Plaistow
Plaistow(Bromley): This one's in zone 4 just to the north of Bromley town centre. It's only ever been minor, and before the 19th century was nothing more than a banker's rural hideaway by the name of Plaistow Lodge. Nearby Sundridge Park Manor seeded a separate settlement - now pretty much merged with Plaistow - and won out by giving its name to the local station. Amazingly all three stops on this spur line appear in today's paired-up list, with Bromley North at one end, Grove Park at the other end and Sundridge Park (aka Plaistow) in the middle. Plaistow(Newham): This one's in zone 3 southeast of Stratford. It's medieval in origin, growing from agricultural backwater to a well-to-do village on the edge of the Thames marshes. A population explosion followed the growth of the Royal Docks and the opening of a station in 1858. Today it's mostly Victorian terraces and postwar rebuild, a seamless townscape which the well-to-do generally avoid. Battle of the Plaistows: Newham's Plah-stow is far more significant than Bromley's minor Play-stow.
Southborough and Southborough
Southborough(Bromley): This one's in zone 5 near Petts Wood, i.e. yet another paired-off settlement that's in or around Bromley. Again it's originally named after a single house, in this case a 17th century outlier called South Barrow. A station called Southborough Road opened in 1858, but that got renamed Bickley two years later because Bickley was closer, and the area remained hamlety until the 20th century. Southborough gained pleasant suburban streets around one very old pub, The Chequers, and continues to be overlooked. Southborough(Kingston): This one's in zone 6, sandwiched between Surbiton and the Surrey border. Surbiton Common was uninhabited before a house called Southborough Lodge was built in 1808. Leafy avenues arrived in the 1880s and extended further after the big house's estate was sold off. The Kingston bypass burrowed through in 1927, hence Southborough's best known landmark is the Ace of Spades roundabout, but that's a bit marginal. I do not have a photo to show you, sorry. Battle of the Southboroughs: Both are lowly outliers unknown to the majority of Londoners, but I'd say Bromley's trumps Kingston's.