Try Frank Pickles.
We took out a policy through them with Highway/LV in June 2011. When our van was "visited" by Asda and a neighbour the following December we received full settlement in only 6 weeks despite there being two crashes and Christmas/New Year in between.
The supplement for our current van (higher value) was very reasonable and the renewal amounts since have been as well. Because of that and the great service we have stayed with them and not bothered going elsewhere.