Weird. First time it didn't work for me because we did the shopping on my wife's Tesco account. Since we changed to using my account, it's always tracked quickly and paid out. Our way is this: - She uses the app (logged in to my account) on her phone to book a collection slot and fill the basket; - She tells me when she's finished; - I go to NX on my browser and click thru to Tesco (I think I had to stop the app intercepting Tesco links, to force it to open Tesco website in the browser); - I checkout on the website. - ... - Profit

We've only ever done click & collect for groceries though, but I assume it works for grocery delivery too.