I tipped at the ZB hole sainsburys Basingstoke, normally in and out in an hour, the chap in the window can see how many pallets have been taken off and how many are left to tip.
They tend to pull a pallet off, scan and check then go to the next one.
The waiting room is ZB but you can use the canteen, 1 driver went to the sainsburys drivers waiting room and smoke shed, he left his number with goods in and they phoned him when he was on a green.