mk1-forum.net

If you're looking for neoprene sheeting material, any size and thickness, get onto HGL supplies on Ebay. Brilliant service. I have used 3mm and 1mm for plenty of jobs on mt Cooper S and Rover Cooper sport over the past many months. 3mm for fuel tank support and upright etc etc and 1mm for between fuel tank straps and tank. Also as a layer between the master cylinder bracket and bulkhead and bracket on the other side too. Generally everything like that has a neoprene seal now

I've done the same with the bulkhead plates, but grabbed the offcuts from a garage roof being done down the road as I'm a stingy old git The offcuts are about 2ft wide and 13 or more yards long... so watch out for any flat roofing going on in your area.

Edit: they have some useful stuff on eBay