I am looking at how I can be more Tax efficient with my BTL property

Currently it is in my name and I am a high rate tax payer, my wife is a low rate tax payer. Using a Declaration of Trust, I can make my wife a joint beneficiary, and can split the income from the property 50:50

As the mortgage is in my name, do I need to split the mortgage interest 50:50 or can I declare that just on my return, therefore I generate less income on my share of the property?