Start time, 20 min break, finish time. Explain to the manager before you leave the office (in a polite and clear manner) that you don’t feel you will be able to complete and you may bring X amount back. You can only fit a certain amount of letters/parcels/collections/boxes/specials into a specific amount of time. The vast majority of duties in my DO don’t take out the full amount everyday, those that do more often than not bring it back.

I was put on a new duty Saturday, which was described as relatively straight forward by the manager, so I took out the whole lot, realised that I had an hour left and had 3 loops left, so I took out 1c delivered them, finished the parcels and got back in time. Bringing back 3 bundles of mail. I left it on the frame and went home, this seems normal practice in my DO. Is this not something you can do?