Its a bit new for me but get yourself a copy of Guzziology
https://www.gutsibits.co.uk/pr/TheShop/ ... esc#topbar
As your not allowed out now you could easily do it yourself.
If your bike has a centre stand put it on a lump of wood to get the rear wheel a bit higher. However there is no need to take the wheel out to get the back brake off its only likely to be held on by a couple of bolts. It's more than likely the one of the calipers is stuck.
You could totally remove the caliper so you could do it in your house (which would mean clamping the hose or leave the hose attached and work with it attached.
Either way unbolt it and take the pads out, new ones needed as they will be fried. See if you can pump the pads out. If one is stuck you will need to hold the moving on back. Use a G clamp. The siezed on can be forced back with the G clamp as well.
Caliper repair kits are available from Gutsibits.