Thanks guys, just to recap. I now have both engines apart, the old one in a trailer and the new on in the Series. The block on the old one is probably a gonner, its blown 2 head gaskets in the same place and the liners are cracked at the same spot. It looks like there are burn marks on the top face so I'm not confident new liners would cure that. Intersting that the old engine has little wear on the liners but big cracks - 1" circumfrencial! but started and ran well. The "new" engine has very worn liners but no cracks. Its also only had one piston with a full set of rings and I think that its the one that fired when starting, it looks like a newer piston. Bottom end on the new engine is better. Pistons in the new engine are scrap - ring lands came out in bits but pistons from the old engine look good with good rings. I'm now between 2 options: 1 hone the bores (hone on order £17) to smooth the steps, fit new rings (£7.50 set) to the pistons from the old engine and back together with new big end shells (£20). It may run ok, - compression was over 200 psi with rings missing and lower limit is 300 so it may reach that. or 2, find somethere I can beg borrow or hire the sleeve puller, they are (£550 to buy) and pull the sleeves then new sleeves and pistons - whole set with shells is about £350. I'm going to ring round the local boat yards and see if anyone has one, preferabley with someone I can pay to use it! I'm OK about pulling the sleeves out but pressing the new ones in looks like it could go very wrong.
I think the engine was being started with ether and that did for the ring lands. I took it for a drive - epic blow by, and it stalled but hot restarted, and still got up to 50mph, and that is with at least 2 compression rings out on 3 cylinders and no rings lands on 2 pistons, so these a tolerant engines. Gmacz- I don't think the gaps will come up right, but with 3 compression rings and spaced at 180 it may work?