Showing a generic error message was not the out-of-box user experience I would have expected Cannot create account "Something's gone wrong..." .
I was hoping to just get a “pending” while things were pending. To be honest I was also surprised that it took more than 4 hours to be “approved” on the Support forums as a new user too, that indicates to me at least that someone had other fires to fight (London city clearly did on Tuesday, but that’s another matter I hope.)
But I’m 100% happy that all things linked up once I got past that “broken” approval pending screen.