Landlord wont do repairs, use deposit as rent?

Zebrauk82

On November 2017 i notified the landlord/letting agency that there was an infiltration on the main bedroom. A roofer was called and he said it was the drainage pipe blocked, but the infiltration continued, in July that became a hole in the ceiling.
My wife got pregnant in march, and baby born in December. We prepared the second room as nursery, put new wall papers, painted the whole house (by free will, not expecting nothing back, been a tenant for 8 years, never delayed rent, I also put a shed in the garden, oiled the deck and fix kitchen ceiling).
My problem is that that the humidity and mold that enters from the hole that give free access to the roof dust, is not safe for an one month baby, when rains a dirty water drips continuously.
So since baby is born 45 days ago, we are staying in the downstairs living room, and never used the nursery. The whole bedroom bean is rotten, the ceiling along it is fluffy and crumble if touched hard.
The builder said they will need open up the ceiling to change the beans, the house will be a dust/dirty environment, also the roof will need work as it is flat and the water sits on the collapsed area.
I'm thinking about saying to the agency they will need accommodate myself somewhere else, or I'll move anyway, as the repair environment is not safe for a baby that not even started vaccinations. I'm not risking that for any follow up that might happen.
And with baby expenses, I can't really afford 6 weeks new deposit for a new flat.
Any suggestions?
Thanks