Hi,
This is only loosely linked to the above but it may be of use.
I get DLA with the higher rate mobility and was toying with the idea of using the payment to get a vehicle. I was unsure whether I could do without the monthly money for 3 years of the contract. While talking to the dealer he informed me that if I were to purchase the car either outright or on a loan he had a form that I could sign to remove the VAT from the car! So with a down payment from savings and the VAT off, a bank loan worked out about £70 per month cheaper than using the DLA. Of course the down side to this is that I pay for the upkeep of the car (tyres, insurance, servicing, etc) but I can also sell it later if I want or have to.
The VAT was worth around £3,000 off the price.