Re: Not more confusion!
I've been registered with the Gov Gateway for some time (indeed, I have the unfortunate problem of having multiple GG credentials for various reasons).
Somewhere in the run-up to this year's self-assessment deadline, HMRC/Gov.uk decided to add an SMS "2FA" element to the mix, and made it mandatory, with automatic enrolment upon login. So when I came to do my return, I couldn't even start the process until I'd faffed about with this useless extra step.
Next time, I'm going back to a paper return - it's easier!
Biting the hand that feeds IT
