hi just a question,my the agency i work for has to have written records of all working time ,POA and other work so do i put down other work has when i started and finished at the place i go to? i mean sometimes i am waiting over an hour before i get loaded and my truck sorted and tacho started that goes for when i finish and i sometimes have to wait 30 or so mins before i get my sheet signed off would clear it up for me if someone could answer my question thanks 
Your best bet will be to ask your agency what they expect you to put down
I would say, use Other Work, for periods waiting for the client to sort out what they want you to do etc. POA would do equally well if you are paid for POA. Using that will leave more time for more work you can be paid for. You know roughly how long you will be waiting from previous experience.
Are you allocated a truck, which you then put on a bay or loading area? It is then loaded while you wait. Then, when you are ready to leave, you put your tacho disc in?
If so, you should be putting your disc in as soon as you get to your allocated truck.
Or are you are waiting around while the truck is loaded, then they tell you that this will be your truck and its now loaded?
If so you should mark on the back of your disc either Other Work or POA from the time you arrive until the time you put your disc in. Also from when you take your disc out until your shift has finished.