Hi I've just got a mk2 face lift Would it be possible to put a mk3 head unit in my mk2 facelift and it work 

In short, no.

 

Longer version... They are physically very different. The MK3 has a two part headunit so the main body is in the glove box and it's just a screen in the dash. Even if you do found somewhere to mount it, I doubt it'll integrate well with the car as the MK3 is MQB platform and the MK2 FL is PQ35 which are completely different.

 

If you want a MK3 'style' headunit, you can fit a MIB STD2 PQ headunit from the later Skoda Yeti's (around late 2014 into 2015 I think?). They are physically the correct size and integrate perfectly with the car. You'd need a small wiring loom adaptor to convert 40 pin quadlock to a 52 pin quadlock. If you want to use Android Auto or Carplay, make sure you get a headunit from a car built after May 2015. Earlier versions only support mirrorlink.

 

Final part of the problem is having component protection removed. There are a few people that can do this now but it typically involves sending the headunit to Poland/Russia and probably costs around $200. They can normally activate all features which is nice