Lambda size

Hi All,
I'm going to have to replace my Front pipes on our 99 4.6 P38, and as they've been on there since new I'd imagine my chances of removing the Lambdas is close to nil. The pipes are the 4 lambda hole ones but with only 2 (front) lambdas fitted.
Can anyone steer me in the direction of the correct size socket to remove / replace these and clarify the Original part number - it looks like I should be going for MHK100940, but maybe not as they're listed for 00-02.
Thanks in advance...

You might need AMR6244
Oxygen Lambda Sensor P38 97-00 AMR6244 Island 4x4 - Specialists in Land Rover and Range Rover Parts and accessories for all models. UK and worldwide mail order.

MHK100940 from chassis No (V) XA 410482

You need to check your chassis No as you may be close to the changeover?? (Thor engine).

Should be able to remove old ones which will help in identifieing which ones you need.

Thanks for the reply, it's a Thor so I will check the chassis number tomorrow.