Thanks J man.

Yes it was the cheap price that attracted me to the big tanks but I'll take yours and others advice and go for 8 smaller ones.. At this stage at least if i can find them cheap enough.
I'll have about 4 tonne to play with and have to accommodate batteries, sola, generator, water pumps and tools. I was thinking of a battery setup like yours and maybe a generator
on the PTO. Solar panels will be over the roof, should be room for 6 or so.

To be honest I don't know why there aren't hundreds of these on the road already. A decent used twin cab chassis Isuzu can be picked up for around $50K, then another $30K for all the kit.
Cheaper and better than a Patrol or Landcruiser IMO.

On the negative side the ride is a bit firm. And you will need a LR or MR license.