My partner and I are not married or in a civil partnership. I pay the higher rate of tax, and my partner is not employed. We are 'joint tenants' and so officially own the property 50:50. Are we eligible for splitting the profits of the rental other than 50:50? If so, what forms are necessary and what proof is needed? Can I elect to own just 1% of the property? The mortgage interest repayments are more than covered by the rent so my partner is otherwise in a position to cover the repayments and keep the profits.

Please see question 1 above and the answer given. You don't need any forms but you do need a written agreement between you and your partner stating the proportion that the rental income is to be allocated between the two partners. You do not make any election to 'own a certain percentage of the property'. You must make sure that the tenant pays the correct proportion of rent into the respective bank accounts of you and your partner.