Thanks everyone for the help on this topic, I've now stripped the engine back with the head off which I'm working on. Re the block, piston 1 moves side to side a little by hand which I'm guessing is not a desirable feature and I imagine what was causing the rattle that prompted the whole process. I imagine I need to get the block rebored, or do you sometimes get away with just new rings?
Re the block, the waterways don't look great, but per the start of this post, I have a 'spare' block which went with the 'spare' head that I'm not now using. My question is this....can I use the GT6 block (stamped 308759) with my Vitesse Mk2 head. The only obvious visual difference to the Vitesse block (stamped 308143) is that the GT6 block has a rebate at the top of the cylinder bores. The GT6 block is in much better condition than the Vitesse block, hence trying to use that instead.
All help as ever very much appreciated! Cheers
Miles