Seems a damn shame I have to answer my own posts...C'mon...surely you guys know more than me? I only bought into this a few days back. I think the 'A' means it's a Auto engine with an 'Auto' spigot. Anyways, it does have nicely 'proud of the block liners' so I'm living in hope. All I has to do is find a piston to replace the melted one.
Not a clue myself Razzledog, all I can say is if there's no response, then the people who are currently following the forum genuinely don't know. Members Conglomerate & Classic Boy have accumulated a lot of (hard-won I suspect) information on the K5 engine, but of course can't be expected to be on the forum every day. You could try messaging them.
But I think you have answered your own question, the liner heights look good.
Have you searched for & found Conglomerate's excellent post on replacement head gaskets?
On the piston, are you having trouble sourcing one?
Looking at your post history just now, I've noticed some of your Carnival posts are in the Australia forum, which I'll have a look at.