Hi, I'm planning on adding some Bluetooth headphones to my collection mainly for when I'm DIYing etc. so no cables are in the way. I'm happy to pay up to £400. Ones I've seen are Denon ah-ncw500, Sennheiser mm400x (but apprehensive re these as I've always found Senns to be to refined/smooth with rock), Harmon Kardon BT & AKG K830. Any advice would be greatly appreciated.