Thanks Ian. The 5x7 looks like it could fit into that as it is 11B601C94 (although I would have bought it sometime after that), but the 11x14 code is 15E601C17 and it is perfectly clear, so no chance of it being a 9 instead of a 1. The 601 certainly looks to be the product code for FB Warmtone as I have some 8x10 RC Warmtone coded 27E803C89. This would suggest 89 as the year of production, but I didn't set up my darkroom here until 94 at the earliest, so maybe that was old stock I bought at the time.