Painting unprimed walls

[Grinning Grandad]

My daughter has recently moved into a newly refurbished terrace house with all the newly plastered walls painted in magnolia. She has just painted over the walls with a colour of her choice but she is finding that the paint is scratching off very easily. I asked her if it scraped off easily before she painted it and she said that it did. I am assuming that a mist coat wasn't applied before the original coat. Is it too late to apply a primer now that two coats have already been applied or does she have to sand it right back to the bare plaster and start again?

 

[KenGMac]

Morrissey, good evening.

Question? was the original Magnolia matt or did the emulsion have a sheen indicating either eggshell or something?

Ken.

 

[Grinning Grandad]

Hi Ken, thanks for your reply, the original coat was Matt, the one she has added was Matt also.