If you tell your landlord about repair problems but nothing is done within a reasonable time, you can carry out minor repairs using future rent to cover costs. You should never withhold your rent just to protest against disrepair!!
Whether you have a written agreement or not, the law says there are some repairs landlords ALWAYS have to do.
Your landlord has to repair:
The structure (roof, walls, floors and windows) of your home;
The outside of your home, for example, the gutters, drains and pipes;
Installations for heating water and space heating;
Baths, sinks, toilets and basins.
If the boiler is that bad, she can get British Gas out if it has the slightest whiff of a leak and they will condemn it. If they do that, the landlord HAS to fix it!!
The other option is to try and get a receipt of repair notices served by the Local Authority. The problem is that the laws concerning housing and welfare rights are very complicated. Local authorities have wide powers to make sure all homes in the borough are fit to live in. These powers cover both large and small repairs but Environmental Health Officers (EHOs) can inspect rented properties, and draw up lists of repairs that the landlord has to carry out.
If landlords fail to carry out repairs within a reasonable period then in some cases the Council can carry out the work and recover the costs from the landlord. Occasionally landlords can claim grants to help pay for necessary repairs.
Because of the formal procedures EHOs have to follow, it may take a long time before repair works are carried out, but emergency repairs are dealt with more quickly.
If you ask an EHO to inspect your home, they do not have to tell your landlord or the court how they found out that your accommodation needed repairing.
As well as the Local Authority taking action, you can take your landlord to court to get them to do the works and/or ask for compensation for any damages to yourself, family or property.
This is a big step though, and before you start you should seek legal advice, especially as you may need to be represented at court. If you are getting benefit, or are on a low income and have little savings, you may qualify for Legal Aid to help with the cost of going to court.
Was the eviction notice granted by the Courts??
I'm sorry it's long winded honey, but it's somewhat of a minefield. You know where I am if you need any further advice.
With regards going to the CAB - there are laws to protect her from any harrassment from the landlord so she needn't worry about that!