We can only advise on the basis of the information you've provided, and this is quite a complex area. We have to assume that you don't have a 'company car' option, as in most cases a regional sales manager would be in the 'job need' category. Company car provision for this type of role would be preferable to a 'car allowance' giving you the responsibility to procure your own vehicle. Car allowances vary according to the type of industry you work in, but £6,000 per year seems reasonable, if not generous. We are also assuming that your business mileage would be reimbursed at AFR rates. You will, of course, be taxed on the allowance but will then have to fund, insure and maintain the car.