In reply to balmybaldwin:
> 46p (I think) is the current AA recommendation to cover wear and tear etc.
HMRC max is 45p, above that there is technically a tax issue. But it includes a contribution to depreciation etc. The lower >10000 miles HMRC rate of 25p per mile is intended to cover fuel and wear/tear costs only.
A halfway house would be receipted fuel - start the trip full, finish it full.
Post edited at 10:14