Since I posted this
Ive done the following:
Removed all lines from the vacuum tree - no difference.
Removed the PCV line from the carb and sealed it - no difference
Removed the vac advance from the carb and sealed it - no difference (since has been put back as it was)
Gone around the intake manifold gasket with carb cleaner - no difference
Gone around the carb gasket with carb cleaner - no difference
Turned the dist. from pointing forwards to the point where the vac adv line touches the rad pip - from 9 inches at idle to 14-16 at idle. The problem here is that it isnt stable above 1500 (doesnt sounds quite right, not sure how to describe it). This is most likely due to the timing now being shot to hell. Im pretty sure its not a vacuum leak on the engine. Any pointers from here?