If you examine my car, KHP 565V, it was built in August 1979, and carries chassis number TCV200017UCF. From 200001 virtually all Canley cars had the later full VIN numbers. There are no other TCV sequence cars in the UK known to me, and only one other in the world. I know that car 200014 is a left hand drive USA spec car in the same platinum colour, yet this has the full later style VIN plate, as have some other factory TR8s registered earlier than my one. Car 200014 does not survive today as an obvious factory car, yet it might have been. Only a DVLA history check by the owner would be able to determine this.
It is likely that a much larger number of cars were built for factory test and experimental purposes than those that we see today. It is additionally likely that many, and probably the majority, were not ever registered for road use. In car development a lot of cars get tested to destruction, many are used as in-factory mules, and indeed a good number are simply crash tested. So a survivor may be out of a series that would at one time have been more logical.
Going back to my car it has a good history file with it including all V5s and so forth. The factory road registered it in March 1980, some 7 months after it was built. This coincided with the launch of the DHC TR7 in the UK. Form V55 (first registration) records it as a "TR8 V8 Convertible" owned by: "Triumph Plant, BL Cars Ltd, Canley, Coventry". It was allocated the Coventry registration KHP 565V. A later official corrective action report from the (then) DVLC has the hand written words: "The V55 confirms that this vehicle is a TR8 prototype. Please amend the description to Triumph TR8 Convertible". The current V5C carries this description today. The car remained in Triumph ownership until 10th September 1981, so the works effectively owned the car for over two years. Given the chassis number the car was probably built as a USA spec, and most probably LHD, yet it has never been out of the UK and left the works with a UK specification 9.35:1 CR engine, in an experimental series, and an automatic gearbox. This is known to be a factory substitution, and is the same drive train as another very similar factory car. The latter however carries an experimental identifier X9** (I am not recording too much detail here on purpose), rather than a VIN number on the chassis plate. 565 was also presumably at one time converted to RHD, and some people suggest that this may have been at the works. There is no evidence of such a conversion; even the little TR7 battery tray is correctly present in the engine bay (TR8s have a boot mounted battery). The previous owner converted my TR8 back to its original 5 speed specification as the chassis number suffix suggests. (UCF: USA spec, catalysts, five speed). The catalysts have long since gone, as the UK spec engines never had these. KHP 565V has a number of other UK specification features.