CGT on the sale of a self-build furnished holiday let

[davesturgess]

In 1999 I bought the plot next to our house and built a 3 bed property on it with the intention of holiday letting. We have done this successfully for 17 years and now want to sell. I did most of the work myself and have only found some of the receipts of the materials I used. The plot was bought for just £8000 because of an access problem which we resolved. In total I can only prove total costs of £14,500!! The property was valued in its first year at £75,000 and it is now worth £225,000. HMRC have told me I am liable for CGT on a gain of £212,500, which is absolutely ridiculous . They wont accept the £75000 valuation made in 2000 as it includes my labour.! Is there anything I can do to decrease this massive perceived gain?

[maths]

The capital gain is the difference between disposal proceeds less deductible costs (the latter not including one's own labour).