Hi
It sounds as though the form is nowt more than a consent form and if that is the case it is odd (but presumably possible) to be charged for that.
With regards to data about you being held on record and the release thereof I can only tell you that if you want to have a copy of the data that NHS bodies have you can sight of that for a tenner.
If you want copies you will have to pay towards the reasonable cost with a maximum of £50.
You basically pay for the retrieval of the data. And although the data is about you, it is not actually yours!
HTH
FD