Yes, I was there while Ken and his mate were filming this at the local 'MV Storage facility'!! Although most know Ken as he frequents most of the forums, the GPW & Trailer are jointly owned by Ken and Mark Payne.
Mark is the mechanical/body wizard, ex-Reme, and did the larger part of the work on the GPW (not taking anything away from Ken here!!!!). He also re-floored the original tub on my MB and did much of the restoration on the vehicle overall (chassis up rebuild in 2006). Mark also helped me with the restoration of my M3A1 Half-track, is currently working on a hardcab GMC353 (of his own) and has 3 other MB/GPW's of his own 'awaiting restoration'.
I wouldn't hesitate to recommend Marks work, he knows modern aswell as WW2 (jeeps, GMC and Half-tracks especially), has the facilities to cope with the bigger jobs, is one of the most helpful people I know, and he charges affordable rates per hour, or will give a fixed price for a specific job.
He's located in the East Herts/West Essex/North London area, but is happy to travel.
PM me if you want contact details.