If you drive a special type of vehicle (that is not a forklift) on the road, you must have a W, T or R endorsement on your driver licence. In addition to holding the appropriate special-types vehicle endorsement, you must also hold the appropriate full class of licence that covers the weight of the special-type vehicle you want to drive.
The course involves theory and practical components. Once successfully deemed competent, you will be given a certificate to take to the AA to have the endorsement added onto your licence. There will be a charge per endorsement for this at the AA. These can be done all together or separately. ITA supplies the machines for the practical component.