Hi Steve,
This is going to bore the pants off you, but here goes:-
Officially all vehicles in the UK should be fitted with amber indicators but It becomes a bit of a grey area on older cars imported from the States. The rules for "The Ministry Of Transport Test" states that cars must have amber indicators unless "Otherwise Fitted As Standard". My 66 Fastback is not converted and this loophole gets my car through it's MOT test every year. It also has no rear foglamps, again not fitted at the time of manufacture so doesn't apply. I've never had trouble from the cops on this issue over a period of 40yrs.
A MOT CERT' is basically a piece of paper that states your vehicle was safe to be driven on the road AT THE TIME OF INSPECTION.
Any car over three years old MUST have a valid MOT Certificate which has to be renewed every year. This along with a Certificate Of Insurance is produced to purchase a Road Fund Licence generally referred to as a Tax Disc. Without which you will definately gain tickets and fines and possibly get towed off to a car pound.
All good fun this eh?
"NEW" American imports have to go through whats known as a SVA test which results in the issue of a certificate needed to register the car and gain a licence plate.
Now I know for a fact that classic cars are imported into this country on a regular basis without conversion and many stay that way. Where the cutoff point comes and the SVA applies I've never needed to know as I've always driven classics but that info is a phone call away as I've a pal that imports.
In the past the fact that you're an American seviceman would have made you exempt from all this s**t but alas it's not the case now, although you should have a fair period of grace before the car requires a British Licence plate. In fact you might not need one at all if you intend to take the car back home, maybe you already have an answer to that one?. Again I can find out if you wish. How long will you be here as I might need to know to find out the relevant info?