Another vote for Kaowool. MJ Engineering do it in small amounts

You could also look at Superwool which is a foil faced ceramic blanket comes in several thicknesses, 6mm would probably do you. Try Heritage Steam they do it by the square metre

Edited By JasonB on 30/10/2014 08:05:32

Hallo Dave…..I will second Lofty on recommending ceramic fibre blanket as a superb insulator, originally developed for use on spacecraft and now used widely in the pottery industry. However the stuff on eBay under Kaowool does look a bit pricey and most of it seems to come from the USA. If you search under ceramic fibre there are some other options. You can also buy it "off the roll" from Polly Engineering (no connection) at about £3.30 for 20" x 12" x 3mm.

Other stuff that I have used with ceramic fibre is an adhesive and a rigidiser to stiffen it up. These things are available from pottery suppliers.

Mick