Have noticed over the last week or so when the car is first started it runs rough for a few seconds and is chucking quite a bit of smoke out the exhaust. (Looks like blue smoke, so assume it is oil)

It doesn't smoke any other times, only when starting.

Any ideas what it could be?

 

Could be valve stem oil seals,I've had the same problem on two previous cars.
Oil seeps into the cylinders when stood, then burns off when you start the engine.Parts are cheap but the labour would be expensive.If you find the right mechanic it is possible on some cars to replace the seals without removing the heads.

 

Worn bearing on the turbo????