Going to Mongolia and back !!!

Its not that the Jimny is unsuitable but more that there are vehicles considered more suitable. If you do keep with the jimny you need to look at some sort of system to make all the kit accessible. The last thing you want is to have to unload and repack the car to get to your jack or your tools. Maybe make some aluminium shelving to fit on one side.

If you are sat on poor quality roads and need to sustain a sensible speed of 20-30+ mph something like a pajero, disco, cruiser will be infinitely more comfortable.

I agree with all you say about the Jimny. However it was relatively cheap to buy compared tothe others you suggest and I hope will be fairly good on fuel. If it should breakdown irrevocably and I've got to abandon it then, I'm not going to lose too much money in the process. I accept that I will have a better chance of success with a bigger tougher vehicle, but it is a balancing act.
Storage racking seems a good idea and I'll bear it in mind. I'm considering moving the washer bottle forward and then bolting a tool box inside the engine bay, roughly where the washer bottle is located. This will keep most of the smaller routine tools to hand and the weight fairly low down.

Thanks for the advice, please keep it coming.

kind regards, teafortwo0789