http://www.open.ac.uk/choose/vocational-qualifications/ also do the diploma...as do Ncc home learning and other online colleges..
you can do reputable degrees on open.ac.uk and get student loans/funding etc for part time or full time courses.
the theory work on the diploma courses is ok but the practical side is quite hard without an assessor that comes out to observe. This means that you have to collect all your evidence to meet the demonstrate criteria yourself where as if you have an assessor they usually watch you and tick a couple of boxes....which would be so much easier. My friend did a degree through the open university (open.ac.uk) and is now a secondary school teacher.
Im currently studying for the qcf supporting teaching and learning in schools through NCC....its ok on the theory. But quite a lot of work on the practical side...as you have to get witness statements and other evidence to meet criteria and you also only get email support with most of these courses which adds to the headache and you also need to find your own work placement (voluntary or paid).