You wont be dissapointed with the watch once it arrives, trust me!
I've bought 3 Breitling straps from selfridges, all from a guy called Tim, he's one of the supervisors.
First time he served me, i was wearing my PAM 212 on a hirsch strap, and we spoke about watches for a while. He's a nice guy, and will sort you out, no problem.
He's never asked me for a serial number before, so you should be fine.