You can check here to see if your landlord has signed up to a code.
The standards your landlord has to meet will depend on which code they have signed.
There are three codes run by Unipol Student Homes, one for shared properties (e.g. house/flat), one for large complexes (e.g. purpose built accommodation that is a similar size to a halls of residence) and one for managing agents (agents who rent on behalf of landlords and have signed up a percentage of their properties with the code).
These codes are a voluntary set of standards that landlords agree to meet. Each code has a complaints process if things go wrong.