we was in the same sitution as you all we did get a letter from the doctor and our healthvisitor we also got in touch with local council welfare support services, environmental health and our local councilor the council have to remove it because it comes under medical grounds and welfare of all the family
after moving after a month our childrens health improve 100%
it did take from start from finish about a year
but if you dont what to move you have got to report it to the council repair team they have to do in 28 working days
you can still get help off the above even if you dont want to move
hope your child gets well soon.
klondike.