Discussing this with another interested party we came to the conclusion that the HC codes were the wholesalers own codes starting with the supplier Hudswell Clarke and indeed were a comparison with the Feuerhand equivalents. ( Perhaps a range that the reps were already familiar with. ) The P35 designation appears to be the manufactures code and may have applied to the entire range of lanterns. Then they could have been differentiated by the height as they are on the wholesale catalog page. Something like P35/10” P35/12” & P35/14” It does seem to fit the available information. I think this will be what I will use in my own notes until I know any better.
Well, following conversations with another collector it would seem that there are two earlier versions of the Gremlin that I was not aware of. This has led to me publishing an article on the Steam Tent website that I hope is now up to date. Gremlin Storm Lanterns - Wicked Lanterns and The Steam Tent Co-operative Just goes to show what a rabbit hole collecting can be...