And i haven't lived in the uk in a while but Ocado is still doing all the deliveries itself I believe, which restricts it in terms of coverage and availability slots, doesn't it? A British friend was complaining that during lockdown there were never any available slots.

Indeed: founded in 2000.

It's worth noting that off the back of Ocado's success, all major UK supermarkets also offer online delivery. And my understanding is that this is mostly serviced directly from stockrooms rather than going via store shelves (albeit individual store stockrooms).

Ocado started deliveries in 2002 selling products from Waitrose shelves, but it was only in major cities (maybe just London?).

Around the same time Tesco (I can't find exact dates, but when I started working there in 2004 it had already been around for a while) launched their competing service, however they did so across the whole country (at any store big enough and with enough parking space to support it).