BTW its a 1972 2ltr GTV (carb update)
Ok, progress report. Changed the vacuum pipes, they were tired. Took the rear carb top off and checked the floats. Ummmmm, when I adjusted them they were not both parallel , ie 1 float was slightly higher than the other so no doubt the reading would have been compromised. Anyways, reset them so the are both parallel and the distance is 16.5 and a bit mm as per Brooklands book. Also checked main and idle jets and the are to spec as well at 50 and 135. Hopefully today I'll be able to take the car out for a test drive and report back.....Thanks so far chaps.
BTW Erik have tried various solutions to balance, tubes , carb balancers, following teh book re setting butterflys at rest and then tightening other carb throttle adjuster till it just touches....I am sure its very close but still not perfect. In any event its is probably only the cause of a little roughness if you pull away from idle with a very, very light throttle, if you accelerate normally its not noticeable. (thanks)