How do you adjust the VAT return to reclaim VAT from mileage payments?

I am preparing my first quarterly VAT return and wish to reclaim the VAT from my employee expenses mileage payments. For example, let's say I have done 1000 miles and current HMRC rates state VAT can be reclaimed from the 13p/mile fuel element, i.e. 0.13 x 1000 x 0.2 = £26.

I can't find an easy way to enter this as an expense or cost, the only thing I can see is to manually adjust the return by the amount calculated. If the latter is acceptable to HMRC then fine, no worries but if there's a correct way that someone could point out that would be appreciated.