Correction: paragraph 2, line 2; delete 'Allowance' insert 'Relief.'
Thank you for your support.
Just a brief note on how the gain is actually calculated:
You need an acquisition and a disposal price. The acquisition price is the purchase price plus costs of purchase plus any improvements eg installation of double glazing, central heating, extensions etc, but not routine maintenance. The disposal price is the selling price less costs of sale, advertising, estate agent's and solicitor's fees etc, Take one from the other to compute the gain liable to CGT. You declare the gain on your annual self assessment tax return and if it were say in the current tax year it would not be payable until 31 Jan 16.