Overview: Autumn may not be the time when many people think of hitching up their caravan and setting off on holiday. But as William Woollard reports it is probably the best time of year to buy or change your van and pick up a bargain. On the other hand is it cheaper to rent or buy your travelling home? Tonight's programme also features test drives in the new Vauxhall Cavalier Estate, Citroen BX and the film of the latest big bike from BMW.