Best answer by russg
Yes, I've got that now. What I was actually trying to achieve in the first place was to simply switch my account from a PAYG to a Pay Monthly, i.e. all within idmobile. Due to your inability to do this, I've had to switch to another network and back again, just to stay with idmobile and on a monthly plan!
I note from other Community posts that I'm not the only one who's wanted to do this. Seems like a problem you ought to be able to solve which would improve your proposition.
Anyway, I'm all sorted for now thanks.