Spool of 8mm film (Siddington GL7)

Here's an unusual one, I'm looking for a spool of 8mm film to test a 1970's cine projector I've been servicing for a distant family member. It all appears now to operate but I don't have any film to test it with. Any 8mm film will do , this projector will show Standard 8 , Super 8 or Single 8, e.g. a mysterious spool found in an attic, an old cartoon film, etc etc. It must just have some film sequence and be reasonably intact to be able to test the auto threading and optics of this projector. Many thanks for any offers.