Sebastian is self-employed. He drives a car with an emission rating of 168 g/km and he charges the cost of all the petrol used to his business bank account. In the quarter to 31 July 2021, he uses his car for both business and private journeys but he does not keep detailed mileage records. The VAT-inclusive cost of all the petrol bought in the quarter is £798. How should Sebastian deal with petrol in his VAT return for the quarter?