MAXTHEDOG

Hi All,
So after having the engine light on with no codes a couple of weeks back after reply the battery, it been back twice since last Friday in both journeys. This time it’s thrown codes P0136 & 0141. According to my reader this is the Oxygen sensor 2 bank 1. Post cat? The drawings I have show two sensors but don’t differentiate between them - they’re both called Sensor-Heated Oxygen (T131). Are they identical? Are they accessible (I’m guessing not really)? Looking on the MGOC site there appears to be three listed could anyone confirm the part number. Is it worth doing both now?
On a completely different subject, the dipped beam is playing up by delaying lighting the first time it’s switched on. Once it on the first time it can switched on again perfectly. Is the switch mechanism in the stalk or is there some kind of linkage to the switches in the steering column?
Any help would be greatly appreciated before I start to delve into these issues.
Regards,
Michael.