Buttons, from what I can gather, St Christophers/lockets and id bracelets became fashionable together (here at least) in about '66/'67
'66/'67 Id bracelet*, photo taken before wrist turned green(Sorry, I know this pic. has been posted a few times already) BTW That's a tie stud worn with a stripe in the tie and not a St. Christopher worn over the top like Del boy.
*Obtained from the fun fair?
John's Children '67 Buggers for a necklace.
Mick wore a watch,...