It's 22L, not 021 or 02L. They never made an axle with those codes.
Defender 90 front axle.
https://www.lrworkshop.com/axles-differentials/axlecodes
You old gits are your own worst enemies!
Post big pictures, not postage stamps.
Clean the mud...
If you have enough space you could use a stainless steel exhaust reducer that matches the sizes you want and then use fuel safe pipe for the rest. Could probably get an exhaust bend either made up or off the shelf if needed.
Don't know about this car but on at least some it should be manual until you press pass the resistance at 100% throttle to the kickdown button which will override your gear selection