decided to have another look at my brakes tonight and finally freed the stuck pad - only took 40mins of me pounding it with a hammer and screwdriver but the bugger is finally off!
Went to do the other side and it was all sorted in 5 mins so at least I know that it's within my limited mechanical abilities to change brakes in future - next step is to change the discs myself (thankfully should be a while before there ready for swapping!)