Hi Dark,
I was looking at the same thing a couple of years go, and I remember being told that the oil filter mounting bracket could be unbolted from the block and directly replaced with the mounting from the first engine that used aq cartridge filter: was it from the County? I can't remember, sorry.
I did look it up on ebay though, and someone from the US was selling the bolt-on cartridge mounting bracket. I just had another look, but I can't find one, alas. I found
this one for a more recent engine, but this seller might help with an email.
Cheers, Mike.