Thanks for the welcome and advice!
Liners seemed a bit pricey new but for an extra 100 cowries we could get a full rebuild
kit that includes the liners, new pistons and rings, bearings, front and rear seals
, thrust washers, and full gasket
kit which seemed like a good deal.
The new liners are in and looking much better, especially than the one with the hole in it..
Seems like having isolating switches on your alternator/ starter +ve leads, anodes replaced and adequate coolant
are good things to maintain..