Sounds very like mine

Where various lights come on unexpectedly I’ve found it’s poor earths, If you have the wiring diagram , the colours very simple to identify so it would have been either live or negative issue . So remaking the earths around the front grille always a good start, both front and rear left...

Redo the earths should help

Don’t know the defender but is the thin wire on solenoid still getting a continuous 12v after you release the ignition switch from cranking

Quickest , drop in brick acid for 2 hours I do like the look of that and the best model, cleaned up the original patina will look great

Strange, can you post a pic what you have , mine comes out rhs of tunnel and that’s normal Manual here http://smithies.co.nz/land_rover/ You have original gb and transfer box ?

Gotta be worth trying some rad seal first

Are there 4 holes and definitely coolant not oil?, they’re not on the 5mb but there are bigger ones on my engine on other side, think my 200di has some but sealed off with silicon poss on other side Can you stick a wire in see how deep they go, looks like they’re angled down? Weeping and not...

Another thought is partially blocked jets in carb

Mine is pastel green, of course the other green is a lot darker Pastel Green - 1 litre tin. Brush or spray. SKU: LPG 1 Excl. Tax: £12.95 Incl. Tax: £15.54 Limestone - 1 litre tin. Brush or spray. SKU: LLS 1 Excl. Tax: £12.95 Incl. Tax: £15.54 This was my last order from Paddocks...

That’s a good bodge last ages can’t see it taking any weight if it’s just a sensor. I had mine out a week ago on 10 mile bumpy off road, noticed the vacuum and washer bottle shaken off its corroded mounts on inner wing, so I cut up last of left over floor plate to reinforce inner wing and bonded...

Some holiday reading for you 😀 https://www.landyzone.co.uk/search/6596168/?q=Jerking&t=post&c%5Bchild_nodes%5D=1&c%5Bnodes%5D%5B0%5D=6&o=relevance

Are the individual sections of linkages moving smoothly without stickiness, you would need to disconnect them to test though

Perhaps a split in pick up pipe and when you went uphill this allowed it to suck in air

Loose engine mountings moving throttle cable ?