I see Lr supermarket ( and preumably some others) sell a differential repair kit for £90 -includes bearing, seals, haldex fluid and diff oil.

Anyone done this?
Is it reasonably straight forward-?

I've never done it, but I think you need some special tools to fix the rear diff. I was chatting to the LR indy that services my car and he said that he bought the correct tools and has done loads of these repairs. Black MY2013 SD4 GS Auto, Wood Company Armrest, Freel2 sticker.
Gone MY2010 Freelander 2 Manual TD4.e S, Alaska White.

I looked at this when my diff went. The tools were so horrendously expensive that an off the shelf re-built diff for £375 was the cheapest option. On top of that you have to buy the haldex oil and a new haldex seal ring but still good value.
If you are really keen there is a thread somewhere on here about a Russian guy who made his own tools for this job, one of which was made from a Mondeo clutch plate centre! John
07 HSE Narvick Black
Land Rover Series One
Triumph Rocket 111 (sadly gone!)