Do the training course & test through one of the companys that offer it over consecutive days using their vehicle & trailer with your test booked for the final day. Their vehicle/trailer combination will meet the rules & they are teaching you to pass the test.
Be aware if you wanted to use your own that the towing vehicle and trailer must fulfill certain criteria or the test will not go ahead & you will lose your test fee.
Rules for the trailer you use
The trailer you use and the load it carries must meet certain rules.
Your test will be cancelled and you’ll have to pay again if your trailer or load don’t meet the rules.
The trailer you use must:
- be a closed box body, such as a horsebox
- be around the same width and height as the car - you must only be able to see to the rear by using external mirrors, and not through the rear window
- have a maximum authorised mass (MAM) of at least 1,000kg - you need proof to show the examiner, for example, the manufacturer’s plate
The MAM is the limit on how much the trailer can weigh when it’s loaded.
Rules about the load
The trailer must carry a load of at least 600kg. The combined weight of the trailer and load must be at least 800kg.
The load must be secured safely to the trailer. Your test will be cancelled if it isn’t.
The load can be either:
- bagged aggregates weighing at least 600kg, for example, sand, stone chippings or gravel (but not toxic materials)
- a 600 litre or 1,000 litre intermediate bulk container, completely full of water
Intermediate bulk containers are industrial containers for transporting liquids. They’re made from semi-transparent plastic and are usually reinforced with a wire frame.
Bags of aggregate
Each bag of aggregate must:
- be sealed
- weigh at least 10kg (all bags must weigh the same)
- have the weight clearly marked on it
You can also use a single bag if it weighs 600kg or 1,000kg.
Water in containers
Water must be in an intermediate bulk container. The examiner must be able to see that it is full.
All laid out here which I suggest you read:
https://www.gov.uk/car-trailer-driving-test