How can I get into veterinary nursing?

I spent a number of years at college studying for animal related qualifications. I then decided that the veterinary field was where my interest lay. I looked up the routes to getting into veterinary nursing which are either through a foundation degree (I've already got a degree in animal behaviour so this route is not really feasible) and an NVQ route which requires that you are employed by a veterinary practice. This is where the problem lies, I sent my CV out to several approved training practices in the area, but there were no vacancies.It's now two years since i graduated and I have had no luck, I even wrote to a couple of practices requesting a work placement, but they have not got back to me. I took a GCSE in Biology as a nightclass, as I know you need 5 GCSE's grade A-C including maths, english and a science subject. I also volunteer at a local animal charity. I know that they can't give me a job if there isn't one, but I really want to prove how dedicated I am. Any suggestions?