Hello,

I've have just been told by my employer that they have messed my P11D up. I have a car allowance and a fuel card. Initially they thought they just filled in my car details on the P11D and I would have to pay back a small amount for the use of the card.

They now tell me that it is wrong. They have now filled in the form to say that I have used £1148.70 of fuel in the tax year and asked me to fill out a Tax Relief for Expenses form. I have done this and calculated that I have done 4697.70 business miles which should mean I get £1878.68 in millage allowance relief.

My questions is if I have used £1148.70 of fuel (which I believe is classed as benefit in kind so I get taxed my tax band (which I think is 22%) of the VAT on the fuel) how much will I actually get in millage allowance and how much will I be paid in one go - i.e not just taken off my future tax.

Any help would be really appreciated.