I was all set to purchase my tyres and suspension kit this week but have come across this leak from the RHF, what's the story? Is this the front diff leak that the GV is known for? Can someone please shed some light on it?

Should only be the seal. Spray some brake cleaner on it, wipe it down and check for cracks.
These seals go very often as the cv is always rotating with the wheel even with it out of 4wd.
The only way to avoid this would be to install manual locking hubs to disconnect it completely.
I have 300,000 kms on my '01 and have only changed it out once, so it shouldn't happen often.
The worst case is the end of the housing is worn and a new seal won't help that unfortunetly.

Funny to see this post. I just replaced that seal for the 2nd time this weekend. The seal it's self is about $7.  How ever it's a pain in the |removethispart|@$$ to pull the axle out. 

George

i've already replaced mine, only 46000k on it...