Ah yes. I am duly educated. Thank you:)

Since seeing these replies, I've worked out how I got in this mess. Yes - finger trouble. I'd installed the MS software to drive the smart buttons with one...

Spot on! Thanks:)

So we discover there are what I would call 'knobs' to twiddle EDGE, its just seems they are hidden along with the documentation telling you about them. I wonder how many more...

Writing on 21st Dec 2015, EDGE has in the last 24 hours decided to resize everything to about 3/4 linear dimension. That appears to be roughly changing 11pt font (of this website on a 20in monitor)...