Looks like it was the vacuum leak!
Had a listen around the engine and found the noise to be coming from the carb where it meets the inlet manifold. So I put some gasket sealant around the meeting edges, started it up again and could still here a slight hissing coming from the cold start valave injector. Took that out and put some sealant around it again. After letting the engine cool I started it and it has never sounded better!!
I have also started it a few times through out the evening just to make sure and it starts first time spot on!

Still running a bit ruff on the idle and definitely over fueling but this is obviously down to the mixture setting and idle setting which a mate of a mate said he will sort for me as he knows carbs very well and I don't really know what I'm doing with the mixture screws etc....


Thanks again mate much appreciated!