https://help.gosimpletax.com/hc/en-gb/articles/360000808650-Property-Income-Allowance
If your property income is over £1,000 and you’re claiming property income allowance, thetotal amount of the allowance claimed from all property businesses (this includes overseasproperty businesses) cannot exceed £1,000.
Under Property Income, select Property Income Allowance
Enter the Amount
Click SAVE