04 l322 4.4 petrol and on a budget - going to attempt changing both Diff Oils along with the Transfer box - who uses what when pennies are in short supply, she's done just over 80k and by the looks of the service history these Oils have never been changed.

It is all in the wiki

http://www.fullfatrr.com/wiki/Main_Page

http://www.fullfatrr.com/wiki/Recommended_Lubricants .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

I would add to that Wiki list that you should look at the exact specification needed, rather than the brand. I slightly disagree with the "you must only use xxx brand, nothing else will do" assertion that you might read.
The Ravenol range of oils are decent value and much cheaper than some other brands.
In particular, don't be fooled by thinking "it must say JLR on the bottle" - after all, JLR don't make oils and you're paying a premium for no good reason. That's my opinion, at least.

Has the specification really not improved in 15 years?
Surely there are better products to use now rather than original spec?

A wise idea at 80 thou it was the first thing I did when I got my SC at 73 thou .also did a 5 ltr refresh on the gearbox to.
non of them are too hard a job .getting the oil in the hardest bit .I Bought a hand oil filler pump (bit like a giant bike pump which made it so much easier ). I got most of the genuine Castrol fluids of ebay all less than half price of LR just keep looking it seems to come up all the time. Beware the diff oil stinks when it comes out ! Range rover 4.2 SC 06MY.

Many thanks for the advice - chickened out and booked it into a local specialist so I know it will be done correctly - latest pain in the bum is my son breaking the rearmost load cover pin - ordered one but not sure how it fits on?

You should have had a go,these things aren't cheap to maintain at garages the more you learn to do the more left in your pocket.  Range rover 4.2 SC 06MY.

Agree about having a go, but if you have no driveway, or it has a steep slope, then getting under the car can be nigh on impossible - and rather scary! I have a mate with a proper ramp and workshop so I'm intending to do diffs/transfer box and gearbox next week. It saves money of course, but it's also very rewarding to DIY and get to know the car a bit.

Certainly agree with the principle of doing anything that you can yourself - I used to work scrapping cars so I am no stranger to working on them but with Arthritis, heart failure and having had a double Transplant a few years back I have reached the stage where most jobs seem beyond me - serviced my daughter car a few months ago and was crippled for days .