Who needs C1, and who thinks they do but does not
Category C1 covers vehicles between 3,500kg and 7,500kg — the classic 7.5 tonne box van or curtainsider. If you passed your car test before 1 January 1997 you almost certainly already have C1 on your licence as a grandfather right, and you only need periodic CPC to use it commercially. If you passed after that date, C1 is a separate test.
The people who genuinely need it are ambulance and patient-transport crews, mobile-library and welfare-unit drivers, horsebox owners, motorhome owners whose vehicle is over 3.5 tonnes, tool-hire and plant delivery drivers, and a large slice of the events, catering and exhibition industries where a 7.5 tonner is the standard vehicle.
The people who often do not need it are drivers whose employer runs vehicles at 3.5 tonnes precisely to avoid C1 — and drivers who would be better served going straight to Category C. If your ambition is haulage, Class 2 is the stronger licence for a comparatively small extra outlay, and we will tell you so rather than sell you the cheaper course.