can u paint over wallpaper thats been painted wiv silk paint wiv vinyl matt

Yes, you can paint over no problem. You shouldn’t need to key the surface as it would cause damage to the wallpaper. Gray Decorators

No! If I understand you correctly you are saying there is silk paint on there and you want to put matt on top? Normally you would key the paint but you risk damaging the paper and making a mess. If you paint matt over silk there is a good chance the paint will crackle some point in the future because it wont adhere properly. The costly, but effective solution, is to paint a coat of eggshell finish first as a base coat or a high adhesion primer such as Zinsser Bulls eye. That should go over the silk and then allow a good adhesion for the matt paint. It will mean 3 coats altogether though but if you don't do it right you'll end up doing it twice.

Yes no prob. Use a good quality emulsion. I would probably use valspar v700 as its self priming