How is student feedback dealt with for poorly teaching faculty?
There are several mechanisms we have that in theroy should deal with this sort of thing:

All academics must have their teaching observed by another member of staff at least once a year, but ideally once a module. All academics must observe someone else teaching once a year. When this happens a form must be filled in that says what the observed could improve and what the observer learnt that they will implement in their own teaching. 

We have a pretty good staff-student committee where concerns by students can and are raised. We also have student representatives on our departmental teaching committee (see this answer). 

How effective these are is varied. Student surveys make up a big part of who a department is ranked in national rankings, which determines how many students we can recruit. Management in the UK can exert quite a lot of pressure on offenders because there is no such thing as tenure in the UK (although all workers are protected from sacking to a greater extent than in the US). 

But this can be ineffective if: A staff member is important to the department/university for another reason (e.g. very high research income), or the staff member is just so over worked and stressed, that they give up the will to do well irrespective of the consequences - this is increasingly common as enrollments fall and management tries to force more work out of fewer people with less resources. If a staff member were protected by the fact you are leaving soon anyway (it takes up to a year to get rid of someone), I'd say there is not much to be done.