Mech at the honda shop said to check the seals in the caliper and sure enough, one of the seals had appearantly "rolled" in the sealing groove and was binding one of the pistons.
New ones are pretty cheap and im getting really fast at the whole tear down/reassembly/bleeding process, im just a little concerned about all the brake fluid soaking into my skin!
BTW,
I managed to keep the bike on 2 wheels after clipping the tree which completly compressed the B-lever and took the skin off my knuckles.