Hi Lorraine,
I would update your address with your GP ASAP. It's also important to do this to help prevent future fraud in my experience. You just never know what details some of these horrible, yet very clever scammers can get hold of, especially if a letter has went to an old address. If this is too difficult for you to do, can anyone assist with helping you maybes ? You could also possibly send your GP an email address, or download the NHS app and update your details on there. Sometimes when we've lots going on, we forget things, it's known as brainfog - so maybe's it's a term you could use, as to why you'd forgotten ?
Hope this information helps
Chris.