niklaus37217, I like your thinking.
I do have / had an anti-glare screen protector which I have now removed and given a jolly good clean around and under the plastic bezel area. The plastic screen protector could have been affecting it - Its been very humid here of late. And like wise there could have been some muck under the bezel. Anyway I've done as suggested and so far (for the last 8 hours at least) its working perfect again. I’ll give an update in a couple of days. Thank you.