How to get a delivery slot - one website for all

If you monitor the supermarket sites all day long, you find that a few slots can come up randomly at any time of day (at least that is my experience with Tesco and Morrisons).
You can't predict when they will come up, unlike the slots that generally come up at midnight.

I guess that this website alerts people when these random slots appear, but that you will have to be quick off the mark ....

Why are they doing it if they don't charge? Some people just do things because they can!

B9exchange, very useful thank you. Asda and Waitrose have slots for tomorrow here. It will save me time going through all the shop websites when I want to order.

I have twice managed to get a Waitrose delivery slot because I happened to wake up in the middle of the night.

Although OH and I are both well into our 70s and both have Waitrose cards, their system doesn't seem to offer us any favours.

After I had a delivery I asked the delivery man to report this to whoever was up the chain of command.

As a result I did get a call from someone who told me that "We were typical of their demographic" - ie most Waitrose customers are old so their is no way we can get any advantage.

I'll just have to keep trying in the middle of the night.

I am offered slots by Waitrose who emailed not long after the start of the lockdown to say they were giving priority to regular customers. . They were very apologetic about referring indirectly to my advanced years - 72.
Ocado have also emailed offering me priority slots so I really can’t complain
I think the slot booking panic has abated along with both companies taking on extra staff to increase the number and spread of both rounds and of slots.

Waitrose have been dismissive verging on rude.
Their knowledge of geography is abysmal too.

Iceland: no dates available

Shoppingslot.co.uk have changed their tack. I went on the site yesterday, first time for a while, and there were loads of available slots at every single store. I couldn't believe my eyes. Then I looked closer, and noticed a little green tab on each slot, with small print that I could barely read. On closer inspection it read "via Shift".

So I clicked on a timeslot, which brought up a page telling me all about Shift. They will do your shopping for you, for a weekly subscription of £8. It's not the stores that have the slots, it's Shift. Who, I assume, is owned by Shoppingslot.

Would any of you be prepared to pay £8 a week to a company you know nothing about, and trust them to do your shopping responsibly, making sensible substitutions? And what happens if, after they've delivered and left, you find items missing? Or there are items you didn't order? I trust the supermarkets to deal with these issues promptly, but I know nothing about Shift.