Again, thanks for all your feedback guys.
Well, the 3rd coat of plaster is on the ceiling which I'm going to leave until the weekend to dry out. This is the 3rd skim, so I'm hoping that it won't be too heavy for the grab between what was on the initial plasterboard and pva. I did raise this concern with the platerer and he seemed to think it would be ok - so fingers crossed.
I do think I have got to the bottom of the organge peel effect I've experienced when painting the last 2 skims. Rather embarassing, but I wasn't aware of the difference between Trade and Retail paint. I just assumed 'Trade' was just part of the paint's name when I picked the massive tubs up from
Wickes. I didn't realise Trade is much more concentrated than Retail paint so no wonder it was such hard work to put up and no wonder there were dimples / roller marks everywhere!!! I'd have to constantly load up the roller and by the time I'd finished the area to be painted and go onto the next patch it had nearly dried so I'd go over it again - putting on far too much, thick paint.
I did buy some Supermatt yesterday, but being 'Trade' it's probably going to be the same thick consistency? I don't wan't to take any more risks or mess about watering it down, therefore, I think I'm going to take it back, get a bog standard retail Crown matt brilliant white and follow the advice of two 50/50 mist coats and 2 top coats. (Unless anyone can tell me if there is a Retail version of Supermatt?)
Thanks for all your help, this has been a very, very expensive lesson and will let you know how it goes. I just hope the ceiling holds up - bit worried about that now!!!!!
Hopefully a few people may learn from my mistake.