Having just added scans of the 4 missing covers, thanks to Alysoun Sanders at Macmillan for the loan, I've recalculated the number of titles with a unique PAN number and make it 2391. This includes all the ones with just numbers, then prefixed with  GP, G, X, M, T, W, R, E, Z, H  and finally the Pipers. As I'm sure you know the prefix denoted the price as listed such as for Pipers they are XP = 3/6  MP = 5/0  TP = 6/0  EP = 7/6  CP = 8/0  WP = 10/6  OP = 12/0  HP = 12/6  ZP = 15/0.
I am currently adding later titles which had SBN's in a separate section. I would be grateful to hear if it would be more informative to include them on the same page as the earlier ones if they are the same title?

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