The nearest sold properties I can find that matches your dates and price range in Clapham are:
-a basement flat in Salcott Road. Bought in Sept 2005 for £318K and sold in October 2025 for £840K. A rise of 164% in 20 years.
-a 2 bed flat in Macaulay Court, Macaulay Road, bought in 2004 for £225K and sold in 2025 for £410K - a rise of 82%
-a 3-bed semi in Tasman Road, Bought in 2002 for £318K and sold for £840K in 2025 - a rise of 164%
The nearest sold properties I can find that matches your dates and price range in Wandsworth are:
-a 2 bed flat in Eastfields Ave, bought in 2004 for 472K and sold in 2025 for £675K - a rise of 42% (so below the rate of inflation increase).
-a 4-bed terraced in Wellington Road, Wimbledon Park, bought for £522K in 2007 and sold in 2025 for £1.196M - a rise of 129%.
None of these are anywhere close to the capital appreciation of 700% you claim.
Can you provide any concrete evidence of a property that has shown a capital appreciation of 500%+ in the past 20 years - excluding those that have had a significant extension and upgrade?
https://www.rightmove.co.uk/house-prices/wandsworth.html