Just done mine at 8 years old and they required a lot of 'percusion persuasion' with a 1 lb hammer but they did let go after a while. Don't smack the friction surface, it is likely to break and fly off into either a) somewhere you can't find and then will end up in a tyre, or b) your eyes, neither of which is good.

Patience works, and sometimes big hammers, but big hammers always break something when they land somewhere you didn't want them to.

The other thing I have done (on an old Granada) was to heat up the disc where it meets the hub flange with blowtorch (trying not to fry the wheel bearing) and then give it a solid smack with a smallish hammer.  That seemed to work too.

Best of luck.