Can I remove this?
 

As above.

Pipe from assumably emissions related item atop the exhaust manifold. Using jp4 head so will not bolt on!

Assuming it's a breather pipe, again the hole isn't there for it, it comes away halfway down and goes down alongside the oil dipstick. Can I just plug it?

Yes you can, hot air pump pipe to save the world. Tonnes of guides and threads about it.

The one out of the end of the head is a breather transfer pipe to allow crank case pressure up to the head so as not to impede the return of oil to the sump. It was deemed no longer necessary on later engines.

It makes a handy oil return port from your turbo when you decide to fit one. :-)

That's a shout!!!

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Will try that at turbo time. What can I do in the meantime, will it not cause me problems? I'm fighting an air leak somewhere after the head swap already i think!!

Just plug it.

What makes you think it's got an air leak?