Unfortunately it sounds like your diff, try driving it in diff lock (disclaimer, try it on grass so you don't wind up your drivetrain) if it goes away, it's likely to be the center diff bushes as said above. Fortunately though the Lt230 box is simple and the diff can be removed with the box in situ, although it's not much work to take it out completely nd give it a good going over!
the 2 bolts that go through from the front side into the transfer casing (bottom center and in the gap between mainbox and front output housing) need to be 2 or 3mm shorter than the rest. if you have put the wrong ones in their place (easily done as at a glance the bolts are "the same"
if thats the case the bolts will be fouling on the gears inside the transfer box, i doubt any real damage will be done but its something to look out for!
Horizontal band saws are a must have for anyone who does more than the occasional bit of fabrocation! Great things, shame they're not normally cheaper!
Also be careful as the 2 bolts that thread into the transfer box from the gearbox side need to be shorter than the rest, otherwise they will do up fine but will be touching gears inside and create swarfy mess
i measured the length at ride height, then set that length as mid-travel on the slip joint.
ideally, you should measure the length at full droop and at full bump although this isnt quite so easy to do with a leafer.
i rather quite like the mountains, reminds me of the discovery 1 mountain logo they used to do!
if a generic LR could be somehow (subtly) added to the foreground maybe to the left of the URL that might work nicely?
its (to me) the least "tacky" of the lot, (not meaning to offend!)
get yourself one of these, they tell you within seconds whether your battery is good or not. you can get them cheaper too.
if you can't afford that, using a voltmeter to measure the battery voltage while the vehicle is cranking will tell you the same thing, anything more than a 2 or 3volt drop and its a duffer.
I explained in the paragraph above the text, we were travelling in 3 seperate convoys roughly half hour apart, There was a breakdown which bunched us all up at that point. 20 mins later we were all setting off again and waited at a nearby pub before the next lane