Suprisingly smaller/in-ear (I dont like walking around in public with a massive set of headphones) bluetooth or wireless headphones seem to be rather rare, with amazon only giving me a few results.
Pretty much the most overpriced section of the market with most of your money going towards the gimmick rather than towards to quality of sound. I'd recommend you just get a regular pair of cabled IEMs like the Head Direct RE0 because you'll get fair better sound quality out of them than out of any bluetooth headset. Probably cost you around 50 pounds shipped.
If you want a bluetooth headset, stick to a normal one for phone use. For music, there are few good ones and even then most wired headphones give better sound for a quarter of the price.