One option to claim business motoring costs is to adopt the same approach as if you were an employee using your personal car for work purposes. This would mean keeping a note of the business mileage in your diary and then claiming 45p per mile for the first 10,000 business miles and 25p a mile after in each tax year to 5th of April.
The other option is to put your car and all its costs such as fuel, insurance, road fund licence and repairs through the accounts. The car would attract “capital allowances” which is a % of the purchase price and the rate depends on the exact make and model of car and its emissions.
You still need to keep diary to identify the mileage that is business as opposed to private, so, if you drive 10,000 miles a year in your car you need to keep your diary to show the business miles. If this was 6000 miles per year then you then you be able to claim 60% of the capital allowances and running costs of the car
Either way is acceptable and we can help you work out which is best for you as each case is individual