Hi Gerard, The code that you have relates to the lambda sensor detecting that there is a lack of oxygen in the exhaust (A lambda sensor detects oxygen content) No oxygen = Rich, Lots of oxygen = Lean. The engine will naturally fluctuate between rich and lean as the fuel system adjusts itself but over time alternating between rich and lean will equal and average of just right. You sensor is detecting rich all the time, normally not a lambda fault. It is only reading what it sees, however you are burning an excessive amount of oil that will expel into the exhaust as it is burnt and clog the sensor up. You need firstly to resolve the excessive oil consumption and clean or replace the lambda sensor if it doesn't clean. Then you can work on trying to resolve why the fuel system is constantly rich. An engine temp sensor fault will cause excessive fuelling if it has been reading that the engine is cold constantly. But you really need to sort the oil and dirty lambda before you go looking for any faults as these will give you false results.
I hope this makes sense and helps. If not or you wish to ask more questions then please feel free to do so until you are happy.
Forgot to say that bank 1 is before the cat and bank 2 is after the cat.