You forgot to include the 3 hours it takes to get to the test centre, do the test, and get back to the yard. Plus usually you get an hour before your test to warm up. It all costs diesel.
Your calculations should be based on 19-20 hours.
Unless of course you are lucky enough to have your training at a DSA approved training centre that doubles as a test centre 
When I did my cat C I had 5 days of training with a test on the 6th, although those 5 days were for 4 hours a day.
Another thing to bring into the mix is the trainer angle. Another chap was in at the same time and he had a different instructor every day and ended up failing, whilst I had the same instructor for the majority and passed. There was one day I had another instructor but he just pushed me harder…
When I tried for my licence back in 2003, my 4 days of training was for 5 hours a day and there were 2 of us in the cab with one trainer, so then I had even less training!
For PCV I had 8 hours a day for 6 days in the week that were supposed to be 2 trainees to one instructor but that soon fell through when the other guy couldn’t get time off from his evening job in a restaurant. But I also spent 2 whole days of that training in the classroom and not on the road.
Gogan:
I’m going to be a bit less polite, and suggest that someone is telling lies somewhere, or at least starting a few chinese whispers!
Hi Gogan,
It wouldn’t be the first time that somebody has started a rumour, or posted incomplete initial info in here.
Gogan:
I’ve never known it to take 30+ hours to train someone to test standard in a single week, though I admit I am not involved in the training training industry directly.
From my limited experience as an LGV instructor (a couple of years some time ago,) I’ve known some people to truly need 30hrs, and in some cases even more, but I’d say that 24hrs on-road tuition for Cat “C” is about average for most people.
Current LGV driver trainers might care to give their opinion as to the average these days. 
Being equally forthright in giving my opinion, I’ll add that the quality of candidates does vary considerably, but we can’t forget that people absorb info, or learn new skills at different rates.
berk:
some companies do 2 trainee at a time + most trainees fail at first time and they charge you £250 to £300 for retest and doing nothing just drive to test center wait 1 hour and come back.
Cant quite agree with this statement. I doubt that many trainers have below a 50% 1st time pass rate meaning that in fact most trainees DO NOT fail first time. As for the retest part I have worked with over a dozen different schools and have never known it where we just drove to the test centre and let the candidate go in virtually cold. As an example our retest days generally consist of 2 candidates that both start at 8am with tests booked for 1pm and 2.30pm. That is a minimum of 4.5 - 5 hours training between them before the tests.
dieseldave:
From my limited experience as an LGV instructor (a couple of years some time ago,) I’ve known some people to truly need 30hrs, and in some cases even more, but I’d say that 24hrs on-road tuition for Cat “C” is about average for most people.
Current LGV driver trainers might care to give their opinion as to the average these days.
I cant remember ever assessing anyone as long as 30hrs “hands on” for a Cat C. 5 days seems to be the typical course with about 3.5 - 4hrs actual driving per day. We are one of the companies that operate 4 day courses based on personal experience of how long it takes to get someone to test standard. We typically would not touch reversing until day 3 but would expect most candidates to be at, or very close to test standard with their driving by the end of the 2nd day. We also back up our judgement by offering free retest training so a good pass rate is essential.
LGVTrainer:
dieseldave:
From my limited experience as an LGV instructor (a couple of years some time ago,) I’ve known some people to truly need 30hrs, and in some cases even more, but I’d say that 24hrs on-road tuition for Cat “C” is about average for most people.
Current LGV driver trainers might care to give their opinion as to the average these days.I cant remember ever assessing anyone as long as 30hrs “hands on” for a Cat C. 5 days seems to be the typical course with about 3.5 - 4hrs actual driving per day. We are one of the companies that operate 4 day courses based on personal experience of how long it takes to get someone to test standard. We typically would not touch reversing until day 3 but would expect most candidates to be at, or very close to test standard with their driving by the end of the 2nd day. We also back up our judgement by offering free retest training so a good pass rate is essential.
Hi John,
I think we can agree that the initial standard of the ‘raw materials’ can be quite various??
From memory, there were some people who were exceptional and only needed 10-12 hours, whilst others simply couldn’t drive a duck to water!!
My “average” of 24 hours came from the exceptionals, but also took into account those with lesser ability, or a slower learning speed, but not forgetting those who nervously went to pieces on test. I still reckon it’s fair to say an average of 24hrs for Cat “C” though, unless the average candidate of today is of a higher standard than the average of those I had about 5-6 years ago.
That’s the problem with generalising, but I’ll readily admit that you have far more experience of this than I do.