I probably should have mentioned I was in Australia. Unfortunatly we're not overly spoiled with choice down here... best price I can get on an H battery is AU $175 (US $130). A stand alone battery would be AU $60 (US $44) = a third of the price!!! Hence, me wanting to recycle the original housing...
Saw a 3D printed housing on ebay that was for sale a while ago but it was US $75 (I think) but it is not for sale anymore anyway.
I think I'll give it a shot and see what happeneds. One of my batteries is shot so might as well try before I bin it.