Thanks for the encouragement,
I think I was being a little melodramatic after a tough day! Looks a bit better this morning.
I think the issue was, it was looking absolutely bang on - one of those rare Nirvana moments in modelling where I was 110% happy, then that awful moment when you realise you've gone too far - not to be helped by a final dusting of varnish that looked like I just sprayed it in light gray paint

fortunately, when this dried it went all powdery and it largely rubbed off. Goodness knows what happened there. I was using Tamiya flat base thinned with their lacquer thinners? Maybe the flat base is a different composition to their paint? Anyway, it just about finished me off and it very nearly went in the bin!
It looks fine, but not as good as it was looking - so that's always a bit disheartening. I think decal removing now with all the different layers of effects - oils/ acrylics etc could end up being a complete b*lls up...

I'll crack on now and try and lighten up ...

Guy