Ordering a PAYG Phone from O2 - MyO2 registration enforced or account required

[pgn]

So I finally decided young Quartus here is old enough for a mobile phone (he's been going on about getting one for what seems like ages, and my ears could do with the rest, tbh...). He is, after all, going to "big school" next year, which means reliance on the school bus system hereabouts, so a phone might come in handy...

Off I went, found a deal at a reputable direct seller of these handy devices, then searched and found a better one at a local retailer of flat-pack furniture, only to end up on O2's website where the same model of handset was cheaper yet again than either of the preceding "bargains".

OK. On O2 website, add phone to basket, hit checkout, am prompted for an e-mail address - this *will* be registered for a MyO2 account. Ooops! Quartus has an e-mail address, but probably falls below the age of having his own MyO2 account.

I backed up the truck, logged into my own MyO2, went through the order process, and lo and behold, a couple of days later, phone arrives and this appears in my MyO2:

So my question is, despite the pressure-selling tactics to get an e-mail address for any mobile sold, how do I divest my own MyO2 of this unwanted, and incorrectly identified (I got a Nokia 1.3, not the Motorola mentioned in the screenshot above!) addition to my record? 

How have others handled this seemingly mandated tie-in of (any) e-mail address with a PAYG phone and a tenner a month SIM with unlimited calls, texts and 6GB of data (for the first three months)?

[Cleoriff]

Good to hear @pgn 

[MI5]

Glad it all went smoothly