@DEtheridge
I can say I had the same problem. I seem to get bad luck when provisioning the Apple Watch eSIM (on other networks too) but at least on o2 they did raise a case to fix it. For a while it seemed like nothing was going to happen, but they did manage to fix it. Basically they deleted the previous provisioning attempt which failed (possibly due to overload on launch day). Then I just went back to the watch app and was apply to re-try joining the plan to the watch and it was setup within about 10 minutes. On Vodafone they will just tell you to re-pair the watch from your phone, which of course will never resolve a provisioning issue on the network.
