The tax relief that landlords of residential properties get for finance costs is being restricted to the basic rate of Income Tax. This is being phased in from 6 April 2017 and will be fully in place from 6 April 2020.
For the 2017 to 2018 tax year, you can only claim 75% of the cost of getting a loan, or alternative
finance to buy a residential property that you let, and 75% of any interest on such a loan or
alternative finance payments.
For the 2017 to 2018 tax year the 25% phased in element of the loan cost is dealt with by a reduction in the basic rate allowance.
On SimpleTax under Property Expenses,
Select BANK RELATED CHARGES
Add the expenses category LOAN INTEREST PAID
Enter 75% of the interest paid
Add the expense category Residential Finance costs not included in box 26
Enter 25% of the interest paid