@ Jack re: band flutes in mixed instrument military bands - I have no idea in terms of firm evidence whether F flutes would ever have been used in mixed instrument or predominantly brass bands, but I suspect not from the general impression (it is no more than that) I have developed from reading over the years. Their normal use was in the "corps of drums" and the related flute marching bands. Flute-use in military wind bands was probably mostly somewhat later in the C19th into the C20th and they would primarily have used flutes and piccolos in Eb ("Db"), not the F and Bb trebles.
@ Latticino - yes, that certainly is an F band flute and I agree it looks likely to be mid-late C19th English. Please do post overall, sounding and C#-Eb dimensions.
For your pads, I can tell you I have recently experimented with closed cell neoprene foam, and although I may not have obtained the correct type, my experience of it is that it isn't a good choice. I was working on a flute for a vegan customer and ended up facing a neoprene foam backing with thin silicone rubber cut from one of those temporary sink plug rubber discs (like
this, except I found a black one...). That works well (so far), but isn't preferable to leather. A young friend of mine has a Tom Aebi flute which, when acquired, had (Tom's original) neoprene foam pads - and I really was not impressed by them. I'd suggest using clarinet pads but, if necessary, thinning them (there are instructions on Terry McGee's website somewhere, or I'm sure I've described the process before here on C&F). Those key-cups don't look ultra-shallow and, if you get the right size pads, you probably ought not to need to thin them. If you can't try out pads with the help of a friendly wind tech who has stock, you'll just have to order in the size you think from measuring the inner diameter of the key cups plus the next size down. They come in 0.5mm gradations down to considerably smaller diameters than you'll need. My experience is that you sometimes also need to be prepared to adjust the key action and rise and cup/shank angle by bending the key itself - they are often relatively crudely made and were never set up as carefully as they might have been originally! Floating and re-floating the newly fitted pads and repeated leak testing is also usually necessary - you can't just glue 'em in and assume they'll be OK! Oh, and remember to check the state of the key-beds - the wood around the tone-holes.
