HMRC access code app

[#1]

This is an odd one!

I recently upgraded my phone and the HMRC app for generating login codes now itself needs a code before it will work (this is normal). To get the code you need two forms of ID (see screenshot), one of which is "the year you took out a phone contract".

So (1) how do I find this? My Plusnet online bills only go back 5 years and I can't see it in the control panel.

(2) How on earth would HMRC check?

(No idea why an NI driving licence is accepted but not a UK one; I have no connection with NI).

[#2]

Cant help with #1 as I dont have plusnet mobile. But #2 They would be be able to tell from your credit file

[#3]

You could also check by signing up with one of the free self-checking credit services.  On Credit Karma for example I can see my Plusnet contract there with it's start date.

Alternatively look through your email history for the earliest ones from Plusnet Mobile.

[#4]

Amazingly I found a print of the 2017 "welcome" email from Plusnet mobile so I have the contract start date.

(Several complaints about the acceptance of NI driving licences but not GB ones on the app page on Google Play.