Just remember Arbitrary, when the driver turns up, treat him as follows:
1) Tell him to wait in his cab for an hour.
2) After an hour, tell him you'll unload him.
3) Take his van keys off him and lock him in your garage. On no account allow him access to tea or coffee. Access to a toilet is allowed, but make sure it hasn't been cleaned recently, there's no toilet roll and the hot water supply is turned off.
4) Unload his van. Take your time, anywhere up to three hours will be fine.
5) Tell him his van is unloaded. You can give him his keys back now, but he'll need to wait around for another hour or so for you to do his paperwork.
6) Let him go.
On no account be polite to the driver - barked commands, rather than "please" or "thank you", are the order of the day. If the driver is any more than five minutes late, refuse to unload him, send all the shopping back and refuse to pay for it. If any items are not as they should be, do likewise. If he's early, send him away and make him come back on time.
If you do all these things, you'll be treating the Tesco driver exactly as Tesco treat those of us who deliver stuff to them. Bastards.