Rob,
I don't have any conclusive answer on your questions, but there are a few very knowledgable WW1 vehicle restorers on the HMVF forum.
http://hmvf.co.uk/forumvb/forumdispl...e-WW2-vehicles
Tim Gosling (Great war truck on HMVF) published an excellent book on WW1 trucks a few months ago (Tankograd publishing), that might hold some info for you.
http://www.tankograd.com/cms/website...d-War-One.htm#
Also, this is worth reading:
http://hmvf.co.uk/forumvb/showthread...ck-Restoration
Alex