Small can of worms with the Defenders vs Disco's... Good to see that arguement exists on both sides of the pond and it's not just over here they like to lock horns.
I'll firstly thank everyone for the various responses.
Now to address a few things brought up.
I have no reservations with the EAS, all i've done to mine is change a front valve block, the compressor is on the way out, i've known this for a while and i've a rebuilt spare sitting in the garage waiting for the day when my motivational kick fails to deliver.
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I'll replace the air struts later this year as my car had it's 10th birthday in December so it's going to get that refreshed. I've already done all the wishbones etc with new ones from my local dealer.
Also, due to the nature of my work, the EAS is a bonus for raising and lowering the car for easy access for people. So chucking it away is a no go.
The car will get an IID tool this year as well. The market for one of them has really opened up with bluetooth ability and control via a smart phone or ipad. So some thinking to be done to see what suits my needs.
I had a look for the book. Cheapest i can find is £180! So, that may have to wait a while as that's outside my budget unless you know of a cheaper source?
I've been reading through Aus and African D3/4 users and there are a nice list of spares and "just in case" parts they take along. Brake switches and sensor's are the main ones.
For range, i have the diesel version so range is better for me, could stick a long range tank under it for real range if needed. However they cost and budget is not huge.
I've driven both D3 and D90's. They both have plus and minus points. A lot of my D3/4 driving friends have a cheap D90 for off road use. ( we in the UK are blessed with having loads of the things to use ) There are some lanes that we have driven on that the D90's have struggled up and the D3 has walked up. Plus lanes that the D3 has struggled on that the D90's haven't. The long wheel base has caught me out a few times when doing an off road competition that had courses designed around D90's. It beached a couple of times and i don't have full underbody protection yet to slide off things.
However, when we do go on the bi-annual off road trips, all the D90 drivers give me the fingers as i sail past enjoying what i call "S class mode"
The route i would take is to go from Scotland, through Europe before going down Africa to Cape Town, then heading East to Singapore and then heading home.