The safest way is to use a car auction buying service that actually costs you little more than buying yourself because they can buy on a much lower auction commission than you can. Try: www.carauctionservices.co.uk/ If you go it alone you simply have to have the relevant money in your bank account, register your debit card with the cash desk to bid, and be aware of the commission you will have to pay on top of any winning bid. Also be aware that commercial vehicles are sold plus VAT at 20%, so you have to add 20% plus commission to a winning bid.