Disco 2 Front Diff Oil Loss

Front diff was getting a bit whiny so I checked the oil level, very low, topped it up and all good but has since dropped again and whiny noise returned so constant topping up currently required.

Leak appears to be around the front offside hub/CV joint assembly as that's covered in fresh oil, unless it's travelled down the axle from the diff itself but I can't see any oil trail there.

Questions:
1. What seals are there that may have failed and be causing the leak
2. How easy is it to replace that/those seal(s)
3. Any special tools required (other than a bigger hammer)
4. Time scale and difficulty of task in hand

All advice, instruction and direction gratefully received.

you will have to remove hub and drive shaft seal is in the end of the tube, but its worth checking the ball joints arent worn and have damaged the seal

If you replace the seal buy only NAK brand, any other will fail in no time, meanwhile blow through the diff's breather tube with filler plug removed to make sure it's not clogged cos if it is pressure builds up in the axle and forces oil out at the seal

Anyone help me out with a part number please?

FTC4822 but must be NAK , e.g https://www.island-4x4.co.uk/front-halfshaft-seal-ftc4822-p-37100.html

Great, thank you muchly, I've ordered two just in case the nearside one goes too.

OK, how do you get the old seal out? What "special" tools do you need, other than a bigger hammer?

Claw hammer, who'd have thought it..!!