Only problem with brake rub is it heats the disc/pads/pistons leading to the brake fluid heating up and expanding which then increases the chance of the disc warping but also gets worse until it starts slowing the bike down. At least that was what happened to me.
Cheers. I'll give them a call but..
Its almost doesn't seem worth it for one rear.
I also need to sound out from Berwins whether they think brake rub will fail an MOT or be advisory.
Although I'd probably rather not have an advisory listed on my 1st MOT, especially when I'll be sorting it at some point soonish anyway.