Help with a leak

Last night I started the car up and after a few minutes noticed some smoke. Baffled me at first but after I looked back I noticed there was oil or something dripping from the line in the image. This is obviously what's causing the smoke as its dripping down onto the manifold. Any idea what this line is for? Thanks

Are you sure it isn't a bad Valve cover seal?  It could be that the line is holed, and is part of the PVC system (not Familiar with Carbed Golfs), where you could use Brake-Kleen to clean the line then wrap tape over it, or replace it.

But usually oil off the back side is a valve cover gasket that has failed or the nuts holding it down have not been set to the proper torgue.  87 in/lbs or 9.82nm.

If you have the 3 part gasket and used any sealer on the cork it can slide out of position as you tighten the nuts causing the gasket to buckle and the splash oil can pool and eventually leak.   

If you used the 1 piece rubber gasket and didn't replace the shouldered studs then it will leak.

You can use 1 drop of RTV (red) where the over the cam rubber seal meets the cork, and where the over the cam seal starts on the one-piece.

Oil will collect on the intake manifold and eventually drip on the exhaust.  

I'm scratching my head a bit here. Could do with more pics or yourself following that line the arrow points to, but it looks like the speedo cable? Also for some reason it has a black (burn) mark on it, so quite possible that oil from the rocker cover gasket is dripping onto it and smoking (and making the mark).

Started it again last night and still smoke. Cleaned all the lines off and nothing is dripping from those. It looks like the seal has failed from the picture. It looks like it could be the manifold gasket?  

I'd say its highly likely its the exhaust manifold gaskets leaking. Access is somewhat awkward, might be worth removing the inlet manifold to gain access.

I still believe that your valve cover gasket is leaking at the rear right corner area.

Get a mirror and a good light and inspect the under side of the valve (rocker) cover.  Good clue is oil on the bolt areas.

take the airbox off and have a look, ots probably full of oil from the breather system. clean it all out and remove the rocker cover and clean out the mesh under the breather as best you can. its pretty tight weave unfortunately so its not easy!