I wouldn't bother mate! I've had two sets of "anti theft" dust caps nicked in the past 4 months. These are the ones with the locking pins. Seems that anyone with a bit of force and a pair of pliers can remove them.
Dill been on ebay and cant find them. The problem is that i have nice silver valves and no caps and black ones dont look right. So any source of locking caps will be helpful
Thanks
Lee