Hi * Fanny* I used to be a monthly delivery with Ocado and then when Lockdown 1 happened they were very good and I managed to get a weekly delivery without too much bother.
I do pay monthly (£6.49) for a delivery pass, I regard it as worth it and I think it helped get regular slots.
However, more exciting is that in February they put me onto the Ocado Reserved list, whereby I have the same weekly delivery time reserved by them unless I pause it ( away on holiday, haha, for example) or cancel.
Morrisons have also been reliable and I use them sometimes to top up on branded goods I cant get from Ocado, but which we like to have- toiletries and cleaning products mainly.
Hope things are good with your Amazon order- I read about them starting the collaboration a good idea isnt it.