Stain block shadow coming through paint

[Kjh2023]

Had plastering done in 2021. Only got round to getting it repainted this week by a decorator. (2 days ago)
He advised me to use zinsser bin stain blocker on 2 areas. I did this a couple of months ago.
One of the areas has covered and the other hasn’t.
I’ve spoken to zinsser this morning and they said I needed to cover the whole area with it. Not just spots ‍ I clearly didn’t read the tin and then repaint over the top. (Decorator left me a tin)
I’ve contacted the decorator and asked him if going over the whole area with the left over dulux (Matt) will cover it and he said it should do… I’m doubtful.

Any other advice?
Maybe I put too many layers of the shellac on. If I cover the whole wall with it again with zinsser, is the whole wall going to have a grey tint to it??

 

[aveatry]

Maybe this would be better picked up in the painting section. In my own paint research I have come across this https://www.amazon.co.uk/Zinsser-Gardz. never used it but people seem to rate it.
Hopefully an expert will be along shortly for you.

 

[Kjh2023]

Maybe this would be better picked up in the painting section. In my own paint research I have come across this https://www.amazon.co.uk/Zinsser-Gardz. never used it but people seem to rate it.
Hopefully an expert will be along shortly for you.

thank you. I will re post on that section ‍