London flat paint on wall coming off as chalk

We’re moving into a new flat in London and I was in the flat leaning against a wall. The paint came off as powder onto my jumper. This is incredibly concerning as we have a baby and I don’t want the baby to get powder on hands into mouth or breathe in air. I let landlord know and he’s sending his handyman over today to look at it.

I know LL wanted to get new paint job done cheaply- inspector told me a proper repaint would cost around £6k.

However, I am concerned for the health of my baby.

I have spoken to a residential painter and a friend who is a LL. I was told it could be one of two things. Walls were improperly cleaned, primed and then they used poor quality paint or no ventilation after painting.

Does anyone else have an opinion on this? Also, how do I negotiate with landlord to repaint properly? It’s an investment on both sides to get this done properly, but this is also London, and people are notoriously stingy when it comes to this type of thing.

(Also to make matters more urgent- we’re supposed to move in tomorrow.)

Any advice appreciated!