http://www.lifesure.co.uk/motor-insurance/
Just bought my 1999 Stepwgn (in May 2012), previously been a Mazda Bongo enthusiast ... until the head gasket blew and put it beyond economical repair.
We have been satisfied customers of Lifesure for some time now ... I don't know if they are the cheapest (though on occasions when I have trawled around elsewhere, I have, so far, always ended up coming back to them!).
Even if they are not cheapest ... the customer service has been excellent, and that is 8 years of renewals on several different vehicles.
Worth giving them a try ... and no, I am not on commission!