Sounds like regular build up to me, does the car smoke from the exhaust?
 
Also with those kms I would inspect the timming belt, you would not want it snapping at 6000rpm.

There are two oil seals, keeping oil from escaping from the bearing - one on the intake side and one on the exhaust side.

If the exhaust side oil seal fails then oil will leak into the exhaust system, where it may burn if the exhaust temperature is high enough, or may not. This can lead to different smoke colours, depending on if, or how much, the oil is burnt.

If the intake side oil seal fails then oil will leak into the intake system, where it will be drawn into the engine, and will be burnt along with the fuel, creating blue smoke.

a little smoke is to be expected of turbo's this old but definately worth a check up, hope it all goes well mate.

Yeah it only smokes for a few seconds on startup or under full load but to my eyes it looks like dark fuel smoke not the blue oil smoke.
 
Put it back together today.  Not getting boost up to the boost controller setting (getting 1.1bar not the 1.2bar it's set to) but sounds like I might not have got the intercooler hoses sealed.
 
Apparently timing belt was done 30,000km ago but will try to check it before taking it to the track next week :D