Income Tax Act 2007 - Section 837 - Jointly held property: declarations of unequal beneficial interests states: (3)The declaration has effect only if notice of it is given to an officer of Revenue and Customs— in such form and manner as the Commissioners for Her Majesty's Revenue and Customs may prescribe, and within the period of 60 days beginning with the date of the declaration. This means you have 60 days from the date of executing your deed of trust to inform HMRC about your beneficial shares with your wife/husband.