What make and age is this rifle?

Many thanks, anything is helpful with these old beauties.

The link below I've found helpful

https://forum.vintageairgunsgallery.com/gem-air-rifles/gem-air-rifles/

Good afternoon all, haven't done anymore on this little Gem until today being a rainy Sunday.

I think I may have mentioned before that the only thing missing on this rifle is the spring.

Does anyone in their parts bins have a spring that is 15mm or 16mm(max) in diameter? May have to use a pistol spring. Length needs to me around 200mm long approx (still need to accurately measure this length) but I don't mind if it's longer as I can cut it to length.

got a spring here Will i took out of an old Jelly rifle while back,its 12.5 mm dia and 220mm long 2mm wire,not very strong spring but the rifle prob dosnt need strong spring anyway,yours if you want it,you can try it anyway and bin if not suitable,as will only get binned here.

got give it a go mate,allways fun to bring what looks like junk back to life,and its cool old rifle anyway prob find a cheap springer with good barrel and rebarrel it,been munted to much to be really collectable its valve is as a fun old shooter really.