There seems to be some confusion. Unlike Frazer Nash cars Austin did not refer to their cars as replicas, so if you see a car referred to as an Ulster or TT replica it is a copy and not the genuine article.
It should be born in mind that there are two types of TT cars. The 1929 cars had long scuttles with the petrol tank underneath as on a Chummy and they had the short pre 1928 type radiator. The chassis was based on the 1929 cars with the brakes coupled for the first time by fitting two front brake cables. The crankshaft was a circular web one still with an inch and an eighth crank pins.
The 1930 and 1931 cars used the same coupled brake chassis as the production cars of the time. The engine was stronger and became progressively developed. The scuttle petrol tank formed part of the bodywork and they had the taller 1928/29 type radiator.
There are photos of the 1929 TT cars showing registration numbers OF 1857, OF 1858, OF 3128, OF 3129, OF 3130 and OF 3131. So there were at least six of these. There was also the car with wheel arches shown in Austin Pictorial History. It is not a TT car but is obviously based on them and was probably being considered as a production version. It is thought to be the same one that was owned by Des Montgomery and Harry Fergusson.
I have no idea how many 1930/31 type cars there were.
The few existing TT cars are rather like Triggers Broom or the 100 year old axe which has ten new heads and 20 new handles. I am open to correction, but the only genuine TT parts that I know of are as follows :-
First the 1929 cars. Holland Birkett had a 1930/31 car which left the factory with a 1929 engine. This engine still exists.
A 1929 body was fitted to a 1930 or 1931 Production Ulster chassis by an apprentice and that car still survives.
I have a 1929 petrol and oil tanks, but they are too rusty to use and were only suitable for copying.
Of the 1930/31 cars there is one complete with its original body and I think chassis and engine in Canada.
The late Mike Eyre restored GW 82 after it was badly damaged. He fitted a different frame and had a new body copied from the remains of the old one which I think was scrapped and fitted a production Ulster engine.
Probably most of the remainder of the car is still original.
Holland Birketts car still survives and is being restored and still has its original body.
The Gorden Brettell single seater was made from a TT car and its engine and TT axles are still with it. At present it is fitted with the TT engine that originally came from GW 82.
The Almack Special was also based on a TT car and it was rebuilt into the single seater owned by Robert Cowell. The remains of this car were found in Africa and it is now back in England most of the TT engine is still with it.
Charles Goodacre built up a special TT type car in 1933 which was used by Austin for development. Many years later the engine found its way into the LMW Special. It is now in David Howes car.
A TT car was broken up in London I think in the sixties.
The body was scrapped but I believe that its chassis was fitted with a replica production body and that it still survives in Belgium. The petrol tank, Luvax shock absorbers and some other parts were fitted to a believed Works car which was rebodied with a body copied from GW 82 and is now in Ireland.
Another petrol tank and oil tank survive on David Howes car.