[Leica] O.T. Need some info on old roll film adapters

[geordiepete211 at yahoo.co.uk (Peter Cheyne)]

My friend's great uncle died recently.  He had all sorts of photographic 
treasure in his old house.  Amidst glass plate negatives, and dusty view 
cameras, my friend gave me an APEM folding camera that takes, according to 
the inscription inside the camera, 2 1/2" x 4 1/4" photos.  Now 2 1/2" is 
about 1/4" taller than the only roll film size freely available today.  

I know this is a Leica group, but I am not one to join lots of internet 
groups, I'm only in two, so I hope someone here might be able to help.  A 
couple of hours trawling Google didn't help me.  Has anyone come across a 
store that sells re-spooled roll film in the older sizes?  Or, better yet, 
does anyone know of anywhere that sells an adapter to make 120 film that bit 
longer so that it can fit into a  slightly longer spooled camera?  The film 
this one was made to take is APEM Roll Film No. 241, or Rajar Roll Film No. 
41.  My friend just said, show me a photo taken with my Uncle Ray's old 
camera and you can keep it.

 Peter Cheyne