Training Contracts – Legally Binding?

Hi,
Just wondering if anyone has signed a training contract with their employer? I signed one at the beginning of ACCA and am now sitting my final paper in December. But I am worried I am no longer gaining the experience along side my qualification.
Just wondered if anybody knew if they were legally binding?
I am considering asking them to change it or even get rid of completely, next appraisal coming up in October.
Thanks in advance.
Any advice will be appreciated.
Mel