Hi Jay37 I second the reserve ideas above find a local reserve then start visiting it and just practise.
You could try here
The Animal Ark Home Page (formerly the Norfolk Wildlife Centre) They seem to be in your part of the world I did a wildlife filming course there last year great course BTW.
There is two parts ot the park one the public see all the time and another seperate area they use just for the filmmaking courses if you become a regualer there and speak to the nicely you may be able to perswade them to let you into the other part better still bump into the guys that run the wildlife filmiaking courses
