Hi Steve,
Apologies for the late reply, busy few days.
Weirdly the TV has kicked back into action again. As I mentioned to Stan above, I think turning the unit off at the mains (having put it into standby) might effect it somehow – although it never has in the past come to think of it.
Anyway, as an experiment I’ve just left it plugged in and on Standby, and (fingers crossed) it seems to switch on normally now.
Thanks for your tip though, hopefully I won’t need it!
Best,
Nathan