Just get one from ebay mate, I think pretty much all hdds can be locked... Just make sure you have the correct eeprom.bin before hand... Unless your using a modchip in which case it doesnt matter if hdd is locked or unlocked.
I'm the guy who he's trying to get one for, I'll take whichever one I can get cheapest postage from to Wiltshire, UK. If you pm me your paypal details and postage price I'll get back to you