Per property, not per portfolio
Expenses are allowable against the property they relate to, and a portfolio-level total cannot be split back out at the end of the year. Record it where it happened and the apportionment is already done.
What people forget to claim
- Mileage to and from the property, at the HMRC rate for that tax year
- Professional fees, including referencing and inventory costs
- Replacement of domestic items, where it qualifies
- The finance costs that feed the Section 24 restriction rather than a straight deduction
Mortgage interest is not a normal expense
It is restricted, and it produces a basic-rate credit rather than a deduction from profit. Recording it as an ordinary expense overstates your relief, so it is treated separately and computed properly.
Then the tax pack
Nothing has to be re-entered. The Tax page reads what is here.