Well for what its worth this is my take on things....
Ive had many talks with an MVT verification officer on the subject of jeep restoration and in particular re-tubing.
His stance is simple, new tub, as far as he is concerned it should be a "Q" plate, of couse I am talking about registering for the first time.
Now lets think about this, Mr Smith owns a 15 year old Land Rover, he has an accident its rolled,the body is damaged beyond economic repair. The insurance company,accept the rest of the vehicle is ok and agree a new body shell.
So a major change, should it be re-registered as a Q plate or keep its age related plate ?
I once went to a show, in the midlands, saw a very nice looking Jeep in US Navy colours (blue) I got talking to the owner he tells me that he "commisioned" this jeep to be built by a prominent jeep parts supplier ( he gave me NO name)
He admitted that over 90% of the parts were new or nos, but insisted the speedo and milometer where were original. It was also its first registration.
As far as I'm concerned original chassis, running gear, engine and gearbox, forms a very good basis for an original vehicle. Looking at a lot of jeeps if NOS or repro parts where frowned on then there would be a lot less on the road (good job I hear some say......)
I have a jeep, and there are both repo and nos part fitted to mine, Im also lucky enough to own a GMC and Wc51 which have far less none original parts fitted.
I really believe that some people get too hot under the collar about everthing being original, and to be honest I'm getting fed up with those people,claiming that the poor condition,worn out parts and overall tatty appearance, is in their words "patina" when in fact it comes down to (not in all cases) down right laziness.
Sorry but you did ask !!!!!!