Hi trevrington,
As the disposal is by two people, there will need to be two capital gains calculation, one for each person, relating to their share of the asset.
If you are husband and wife or civil partners, you have the choice of splitting the asset 50/50 or by your legal and beneficial percentage of ownership. For everyone elese, it is only split by the legal and beneficial ownership value.
Please have a look at the guidance at CG15250:
CG15250 - Expenditure: incidental costs of acquisition and disposal
For details of allowable expenses of acquisition and disposal.
Please also have a look at CG15150:
CG15150 - Expenditure: introduction
Onwards for guidance on determining a capital allowance and a revenue expense.
Revenue expenses cannot be set against a capital gain.
Thank you.