If I took my theory and hazard perception test and it is still valid does this mean I dont have to takte the test again, say if I wanted to do Cat D. Or do I have to go back to Jail and not pass Go so to speak 
As far as i know, and im sure ROG will correct me, the Cat D has a seperate theory test (and i presume HPT) to be done before obtaining the licence!
There is a theory and hazard perception test for each main category (A,B,C & D).
So if for instance you passed theory test (both parts) for category C. It would cover you for the whole of that category. No need retake a theory test for CE.
D is a seperate category and so is a seperate test.
(Note C1 and D1 held under car licence âgrandfather rightsâ donât count)
The detailed list of exemptions is under Section 39 of The Motor Vehicles (Driving Licences) Regulations 1996. (searchable from www.statutelaw.gov.uk)
All classes have the same HPT video clips, but you have to do them each for each theory test category. Whilst itâs a separate test, a lot of questions are in common with LGV ones. The question bank is roughly 600 Both, 300 LGV & 300 PCV.
Different theory test for coaches I am afraid although the medical should be fine for both catagories.
Mothertrucker:
Different theory test for coaches I am afraid although the medical should be fine for both catagories.
Provided that the medical is either less than 12 months old OR you ticked both C & D when you applied for your provisional.