Bit late!
I spent all of tonight ringing the number on the Sainsbury’s website to register as a vulnerable/disabled shopper. Only 3 options on the system, none of them say anything about it. Had a Hell of time getting through and almost every time I got the “I’m sorry we’re too busy to talk to you” message before getting cut off.
Eventually got past the first message to choose an option, took over 2hrs to be able to get through enough times to try all 3 options, big surprise, every option ended up with another “I’m sorry we’re too busy to talk to you” message before getting cut off.
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!