It seems that every time we do this we lose at least one bottle of varnish, and it's expensive stuff - the cheapest source in the area charges £2.50 a bottle. I've tried pound shops, eBay, etc. but clear varnish doesn't seem to come up for sale, except possibly as an occasional bottle in a random selection. Metallic purple yes, black yes, scarlet yes, but not clear.
Do any of the Brits reading this happen to have contacts who could sell me a few bottles cheap?