Cheers chaps.
Andy, I've no idea why, but it seems a lot of the early 1975 cars did have the rev counter redlining at 6k. My only possible explanation for this is it was fitted as standard from the start of production, with a view that the V8 option would be coming along sometime soon. So a rev counter covering all engine options was thus fitted.
This is the original instrument cluster for ACG 5, no gauges have been changed, even the clock works. The only other difference is the volt metre is in Green, not the usual White for some reason. There is also a part number scribed underneath the cluster.
TR7 Coupe KDU 366N (development car)
TR7 Sprint ARW 181S (pre-production sprint)
TR7 Drophead KHP 646V (drophead press car)