I recently enquired about an R1 for sale on ebay. What caught my eye was the burner head was the very early type, 1930/40s I think, and copper fire bowl. The seller had restored the heater and had spray painted the tank, even the control cock and to me most surprisingly the back of the fire bowl. I asked the seller if the paint would blister on the back of the bowl and he explained it probably would with enough use, but then the same was true of the painted originals. So here's the question, is the seller correct in saying Tilley painted the back of the fire bowls of some R1 heaters? It seems very unlikely to me for the obvious reason of blistering. However I'm no expert on R1s so I await education.