Other than autotrader – where is good to look?

What make of van?

You could look at some of the enthusiast forums and there is of course eBay.

vivaro/primastar/traffic

toyota hiace

transit/transit connect

oh and the "obvious" – transporters

Good list of options reckon Exchange and Mart, eBay plus of course autotrader, be worth finding some forums for those and see what's on there, is it for work or for bike duties?

Also be worth trying the manufacturer sites and then doing a deal with a dealer.

Talking of transporters….

Finished getting my van ready today for the next part of it's journey from van to bike van

i found a local guy that traded in transporters told him exactly what i wanted and gave him my number.he would ring me up now and then to tell me what was coming in etc. worked great for me.

Some VW ones:
Prices may be a little inflated compared to AT etc. but worth checking.

Volkszone
Brickyard
T4 Forum

http://www.btfleet.co.uk

Local dealers usually just stick higher mileage trade ins through the auctions but that costs them time & money, make them an offer – I've picked up some cheap vans this way.
Failing that BCA vantastic @ Derby or Newport http://www.british-car-auctions.co.uk/default.aspx?page=3218