Conversation between me and two Tesco folk by email in the uppity titled "Tesco Customer Engagement Centre":
Me: The 4 hour slot option is not working, virtually none are available, yet the whole day can have 1 hour slots free. Almost every delivery I get, the driver tells me that he's been given deliveries in an inefficient order. If you fixed the 4 hour slots and people used them, the system could make his route in a more efficient way.
Tesco person 1: I'm sorry you couldn’t get the delivery slot you wanted. Our stores have a limited number of delivery slots which are available on a first come, first serve basis. Once all the slots have been filled, we can't accept any more orders for that day. You can book your delivery slot before you start placing your order. This guarantees you a slot, rather than being disappointed after adding all your items to your basket. Here’s how to book your slot first: [snip]
Me: I don't have a problem booking a slot, I just select one of the 1 hour slots. I was just pointing out that the 4 hour slots are not available when they should be, since the 1 hour slots are available for the whole day. If this problem was fixed, drivers could get more sensible routes, as the customers could be placed at any time within the 4 hours. A number of the drivers have told me they're getting very inefficient routes.
Tesco person 2: I've had a look into this and unfortunately all the 4 hour slots have been booked up. I'm afraid this is not actually a website error. As my colleague advised previously our slots are subject to availability on a first come, first served basis. We know that, during this incredibly challenging time, it’s been hard to find home delivery and Click+Collect slots. It’s down to a huge increase in demand for online deliveries across the whole country.
Me: Sorry but that doesn't make sense. If the one hour slots for 6-7, 7-8, 8-9, and 9-10 all have a free slot, then it should be possible to pick 6-10, and the system will put me in whichever slot ends up free.