My latest theories (porbably absolute rubbish)
I have a resreved slot every Friday. This Friday - got in an amended fine after the huge queue.
They might allow existing orders ahead as they are - they are not telling you to remoove stuff when your basket already has too much of something in (I removed something tried to re-add and was told I max quantity exceeded.)
I think they are allowing already prebooked slots to continue - if you already have 2 orders booked in one week - they haven't cancelled mine or asked me to choose. BUT i think if you have new order - you can't book one less than a week after the last one.
I think they still haven't opened up orders beyond 5th/6th April. Normally you can book 3 weeks in advance.
Reserved - took my smart pass money yesterday, My order for 10th says I have to rebook but I don't know if that's down to no slots being opened for the 10th yet or them having all been booked.Reserved slots are not automatically booking anymore. OCado confirmed that to me.
Item limits - some seem to have limits and others don't. I had a play around. I could only have 2 of quiche, ham and pate. I think there might be 5 item limit on frozen goods excluding icecream. I think there may be a limit on meats. There is a limit on milk (? what), there is a limit onf 2 I think on eggs, and 2 bakery items like bread or rolls.There are limits on baked beans, tinned tomatoes etc, loo roll, soap, tissues, kitchen roll and cleaning products.