I actually learnt to drive HGV'S on a double de-clutch vehicle non-syncro, truth is it was what we called in "The Job" Dennis Rolls.
Basically it was a petrol engined de-tuned Rolls Royce engine to run on the cheapest crap petrol available yet get you there as fast as possible. Here i might add as i just noticed i havnt said what it was , It was a Fire Appliance (or Engine as everybody likes to say)
Now once you have learnt to drive one of these monsters at speed in and out of traffic at ridiculous speeds double de-clutching etc you can drive anything.
What i would say is they were great to drive even with the off-set steering wheel, you used the engine and gears as brakes and could whip round corners and roundabouts with tyres howling and be safe as houses.
When the Brigades started modernising and the semi and full automatics that are used today started arriving driving was never the same and you just could not maintain the speed with the deisels, in the end i found myself using the auto shift like a manual,
didnt do the boxes any good though, blew at least 2 up lol. Brigade workshops loved me 
