I shop very occasionally at Ocado, like once or twice a year where I usually buy a few things they sell that I can't find elsewhere (I have a 'nice things' list where I save ideas, usually that I've read about on here).
When I do order, I've never paid for delivery even if it doesn't meet the minimum for free delivery (at the bottom it says if you spend under £75 the minimum delivery charge is £2.99 but I can see lots of free delivery slots and last time I spent £41 but delivery was still free).
A relative shops there semi regularly, eg a couple of times a month because she can get M&S food delivered instead of having to carry it home on the bus and she was saying how she had to think what else she could buy to bump the order up over £75 so she didn't have to pay for delivery and this got me wondering.
I don't have a Smart Pass but if I ordered something now, I can see that there's plenty of free delivery slots over the next few days.