My daughter has just had the same problem with damp and mould in her new build rented house, the landlord wouldnt do anything about it even after being asked many times, so we resulted in our local enviromental services at the council, they were very interested as its a health hazzard, the work is now being done to put the damp and mould right, try going down this route and see what happens, seeing as your wife is disabled they will certainly do something about it, and i would also say like my daughter is now doing, withhold the rent until the work is completed. Good luck.