Also i would add to polwarts advice and say that you should ask at the CAB for the address and phone number of your nearest Shelter office.They are a charity who work with tenants to resolve housing problems.It's all they do so they are experts.Also try your local Housing department at the council.They should have an enforcement officer who can help tenants with problems.You should get help from either,especially as you have children.
I have used Shelter and the local council tenancy office when i had a landlord problem which resulted in my being illegaly evicted from my flat and unable to recover my possessions from inside as the lock had been changed by the landlord in my absence.
I think shelters web address is
www.shelter.org.uk.
Good luck,chris.