I apologise that this doesn't answer your question directly. (i.e. I'm unable to recommend a solicitor who can handle housing problems on legal aid). However, I hope that this reply might be of use to you.
The housing charity, Shelter, can point you in the direction of relevant agencies across the country. They can give you free advice and, if necessary, they might well be able to direct you to a solicitor who specialises in the relevant field. You can find your local advice services here:
http://england.shelter.org.uk/advice/advice-10 05.cfm
Alternatively, Shelter offer a telephone helpline for initial advice:
http://england.shelter.org.uk/advice/advice-10 10.cfm
There's also plenty of information available within the main pages of the Shelter website:
http://england.shelter.org.uk/advice/index.cfm
Once again, I apologise if I've wasted your time but I hope that, by contacting Shelter, someone will point you in the right direction.
Chris