The Inland Revenue took 4 years to stop asking me for joint tax returns for the business I'd sold because of my dh1's unexpected death - a fact they were fully apprised of at the time.
It took quite a few phonecalls/letters/emails before they could comprehend that no, dh1 was unlikely to be much mithered by however many bloody penalty notices they sent him 'c/o' me...
It's crap, Yorkiegirl. Send them a strongly-worded letter.
(oh & if they 'phone again, just say 'telephone preference service'. You don't even need to actually have it - it works like waving a bottle of holy water at a vampire )