Private residence relief: realising gain: restriction
The second part of Section 224(3) denies relief on the part of a gain which is attributable to particular expenditure. In practice this means a comparison between the gain which accrues and the gain which would have accrued without that expenditure. To make this comparison you will usually need advice from the Valuation Office Agency. This advice should be obtained using form CG20, see CG74320+, with a covering memo explaining the purpose for which the advice is needed.