I charge 45ppm for 10,000mls, then 25ppm to the business through my personal expenses, along with food when on site. When I have needed a VAN, (once in the last three years) I rented one, claimed VAT back on hire and fuel.
Not sure how you run a vehicle at those rates I do all my mileage at one rate regardless of miles travelled. HMRC don't set mileage rates they just tax you on what they consider to be profit i.e. anything over there set limits, also if you carry a passenger for work you can pay an extra 5p/mile for that, the biggest joke in the HMRC allowances is you can claim 20p/mile on a pushbike
With regard to the VAT once your company has paid your mileage it can reclaim an amount equal to the VAT that would be paid on the fuel for each mile you travel, Google "VAT reclaim on mileage allowance" it could save you some money