How to paint over peeling masonry paint

[Linsiloo1226]

We live in a 1950’s house with a rendered panel on the bay window. The paint on the rendering is really old and is peeling badly.

We want to sell so need a quick solution to how to make this look more presentable. Can I sand down the peeling paint and go over the top with masonary paint or will it need a coating of something to repair it?
I’m a total diy amateur so all help is really appreciated!

 

[Wayners]

Picture would help..

Maybe hire a jet wash for cleaning masonry walls or get someone with the kit to do it.
That may take loose off? But we need a picture.
Zinsser Peel stop what you can to bind it.
Paint.

Not ideal to do it until the better weather