Autocarrot - Thank you - I was struggling but managed to get some today - and another MNer has suggested a further pet delivery service, thank heavens.
I have enough in now for us all to stay indoors for a couple of weeks and avoid most shops - we may run out of milk and bread, but there is a small local shop where we can usually get these, though I'd prefer not to go out at all so we may just do without if necessary.
I'm a Sainsbury online shopper, but haven't been offered a vulnerable person's slot - I don't know what their criteria are, or how they know who qualifies. I'm 66 and DH is 73, but he is self-isolating as he has a heart problem and ulcerative colitis. I have Sjogren's syndrome, which is an auto-immune condition, but I've checked, and I don't think it renders me especially vulnerable. I've tried to ring them to see if I could go on the "vulnerable" list, but can't get through - I've been trying all day.
I went out, with disposable gloves, wiped down all of my shopping (including the bananas!) with disinfectant solution, then showered and washed my clothes.
The supermarket wasn't too bad, except that the girl who helped me put my shopping through (I was on a Service-yourself till and there was a problem or three) talked to me for ages, even as I was walking away and nodding and trying not to breathe (this happens to me a lot - I must have a more sympathetic face than I realise - there is often murder in my heart 
). There were quite a few people in face masks, the lucky buggers!
DD has been told not to go into to work. DS and DIL work in a school and are "childminding" for essential workers. I'm worried sick about them.