HMRC managed to cock up by substituting my work address for my home address. No idea why they chose to do this, but I only found out when they sent me a tax code to my work address.

I cannot change the address online because the date I moved into my home address is, oddly enough, before the date they have decided I moved in at work. I tried ringing them but, surprise surprise, I cannot get through to a person.

Bah humbug and damnation.