Just a thought, maybe you could contact Chocolate as she is an NVQ assessor, it may be possible that having done most of your course you could still get the assessement done? That would save the £££ on starting from scratch again. You could buy a nail trainer separately (several on Geekbay I think, and probably on Ebay too) for practising on. Then, if you're nervous going on a course with a group of people it would give you time to get back into the swing of things on your own. Maybe then when you're a bit more comfortable you could go about picking your company. You could talk to Creative and see if they might let you do a conversion rather than the foundation considering you have done such a wide course already, otherwise if it's just for product knowledge (and you're not going with Creative), most companies do one day conversion courses to teach you their individual application techniques and trouble shooting.
It's highly unfair that the college wouldn't let you go on to level 3, blatant discrimination, but I'm sure you're mad enough at them already without me getting you going!
Good luck with what you decide to do, hopefully you can find a way of putting your existing work to good use rather than having to start from the beginning again.
Lol x