I think the real question is one of tax. It can hardly be fraud on his own company, if he owns the company. However, if you have more than one car, I suspect that it makes more sense to treat the car in which you do the most miles as your company car, and by the sound of it, that wouldn't be your Westfield, unless of course your other "car" is actually a work van which is used solely for work and therefor not treated as a benefit in kind, whereas with the Westfield you would be taxed on it's running costs as a benefit in kind, and if I remember correctly on a percentage of it's initial capital cost (although I'm very out of date on taxation, particularly in relation to a director of a company).
I'd strongly suggest that you should be asking your accountant assuming you use one to do your company accounts and tax, rather than on this (public remember) forum.