Its worth doing the training as it improves your driving style. The emphasis is on “the comfort and safety of your passengers” So your driving style is really “smoothed” out.
I know of a coach compant in Luton (very high profile, premiereship football teams, celebs etc) that take you on an assessment drive with a glass of water on the dash. Spill any and you don’t get the job as you’re not good enough 
Semtex:
Its worth doing the training as it improves your driving style. The emphasis is on “the comfort and safety of your passengers” So your driving style is really “smoothed” out.
I’d agree with that. I’ve heard PCV instructors talking to test candidates on that subject. At one place I’ve worked, us LGV instructors shared an office with the PCV guys, and I’m sure you can imagine the banter that went on. 
Semtex:
I know of a coach compant in Luton (very high profile, premiereship football teams, celebs etc) that take you on an assessment drive with a glass of water on the dash. Spill any and you don’t get the job as you’re not good enough
One of the LGV training schools I’ve worked for did something similar for some higher-profile PCV operating firms, IIRC they called it an “advanced assessment” or something similar. The same training school also had their own coaches and double-deckers, and did a lot of training and assessments for “First bus” and Arriva. They also taught Passenger CPCs. I had a look into that, but IMHO, without an insight of my own, it all seemed very strange.
I could easily have done my own PCV with them, in fact they asked me to do it. I don’t know what it was, I just didn’t ever fancy doing coaching, or even PCV tuition. TBH, I’m stuck for a good explanation, but my gut feeling said “don’t do it.”