I used to be with BT untill about five years ago. My log details were still active on my computer and I got my code by just opening the link.
Unfortunately, I could not pay for it as my details were no longer valid, so I opened a new page and created a new account at the bt shop, then went back to my basket on my other page, and paid with no problems whatsoever.
Should get my PS5 this week :-)
Congratulations if you did managed to actually buy one from Argos as we found the stock availability very flaky each time they are supposed to restock and as such did not see a decent level of stock to warrant a stock alert. There was some so called 'glitch' that would allow you to purchase a PS5 console from Argos even though they didn't show any stock and we would never advise to follow this kind of advice as it could lead to more disappointment when your order gets cancelled, you have to wait for a refund and possible banning from the store.