Rear discs on a VW trike

I fitted these a couple of years ago and they are great, however after this winter period layup i rolled the trike out and ran it up, no problem, till i went to ride it into the garage. The rear disks were locked on. when i got the trike out i did pull the hand brake on quite hard as it got near my car.
There are no brake light on indicating a master cylinder problem so i think the handbrake mechanism adjusted itself when i pulled it on sharply. As yet i have not looked at it, i am going to somehow prise the brake caliper off the disc.
Has anyone come across this with rear disk brakes.

Without knowing what your exact setup is, my guess would be the park brake cable has somehow frozen up.
The caliper is likely not the culprit, but will likely have to be removed to access the park brake mech.
Post up a pic if possible...

Seems like you are saying that all seemed ok untill you set the park brake and the peddle and brake seemed ok until then.
If so I would look into the park brake mech.
Just like said above, check the cables.
I think the park function is all mechanical and not hydraulic. The lever on the cylinder and its mechanism in there could also be locked up with rust. See if the cables are tight with spring tension or are hanging loose/floppy at the cylinder.
I think Stinger has the park brake rear disc on his.
Maybe he is more familiar with them.
I have the NO park brake ones. They are the vw "varga style" (oem vender) brake caliper that came on the front of ghias, squares and notches.
I do not know what the park brake calipers came from. I dont think it is oem vw style.