That why the paint coming away, matt emulsion does not take to going over a silk paint very well. You would have been better advised to use the bathroom paint to go over the silk and also use it as a primer (thinned down) over the bare plaster. You may be able to wash your primer off with an abrasive pad (green saucepan cleaning one), failing that a sealer would best be used like Zinnser Bullseye123 prior to the bathroom paint. The bathroom paint is a good product, it is an Eggshell paint that is recommended for areas of high humidity and steam the only thing 'fancy' about it is it is the correct type of paint for the area you would like to use it in.
I'm not fully understanding the work process here (but could be me / Pinot Grigio) Silk paint is a strange beast to both paint with and paint over Not sure why you've 'primed' (mist coat) over the previously painted areas - no need - bare plaster only The silk paint is pretty much non porous, much like the bathroom paint and I doubt the mist coat has adhered to it When you roller on the top coat, the water in the paint will likely dissolve the mist coat and ur sewing it peel off with the roller This can happen when fresh plaster isn't mist coated and painted with full body emulsion It may well stick and look ok. Problem comes several years down the line when you re-paint. As you roller on the new paint, often the whole lot comes off leaving the plaster looking clean and fresh as the day it was applied Would say give the whole lot a sand down to provide a key, say 180 grit, wipe down with damp cloth, no mist coat on previous painted sections and roller on ur paint - good luck
Thank you all for your help. I was thinking after Astramax comment I'll go and get some Zinsser but I would have to sand down the wall ive mucked up anyway. I think you're right I will have to sand it all and wash it down, luckily it's the smallest room in the house!
My mum uses vinyl silk everywhere, her ceilings are all shiny white. Can't stand the look and it always remind me of an old grannys home!