53 plate Volkswagen Polo TDi Sport lambda/02 sensor problems
 

Hi guys/gals,

Looking for advice on 53 plate Volkswagen Polo TDi Sport lambda/02 sensor. It's my old dears car she's just had a warning light come on the dash indicating emissions/lambda drive to nearest garage. Haven't had a chance to go look at it yet as I'm working today. Just wondering:

1) Is it ok to drive for now albeit it will probably be running rich or will it go into any form of limp mode?
2) Is it just the one lambda sensor on the car or several?
3) Is it a straight forward job to replace?
4) Any advice on where to get the part cheap/second hand?