Thanks very much for the response (wonder who marked the second post as
a 'solution'?) I was worried it would end up with something like this -
did you try a SIM swap? That was going to be my first option. This is
also going to be for my work, but as...
@DanielJamesBall - did you manage to solve this? I have exactly the same
problem - other SIMs in the same phone activate perfectly so its clearly
an O2 issue. Tech support say they cannot help though..