So update from MikeB, obviously the wooden skewer fix isn't particularly robust, apparently it managed the first move/relocation but not the next
.
Some bits he told me:
The cable at the front panel end (which you can't really get into) is part of the membrane switches (based on other membrane switch construction he researched) so you can't replace it.
The socket on the PCB is old school (of course) and not used any more (he hasn't found one yet), moreover, they are only good for up to 10 insertions/removals. So don't pull it out unless you HAVE to. Probably I accidentally pulled it out when I changed the display? it's a long time ago. It's easy to dislodge when you change the display as the display connector cable runs under it.
It seems trying to clean the exposed ends (very thin silver allegedly) of the ribbon cable seemed to do more harm than good. Apparently he spent quite a while carefully exposing some clean trace x 10 with a razor blade. Very fiddly no doubt, but he got there.
Next step is remove the PCB socket and attempt to repair it, i.e. bend the individual contacts so they "get a grip" as it were. He thinks they maybe can be removed individually, squeezed and re-inserted?