Think I’d also weld and then redrill…. TIG if possible too.
Have you got a small enough annular cutter or a slot drill for it? They’ll both wander less than a normal drill but if you start getting issues.
As Daan says the AEU2522 early Ninety/Oneten CVs aren’t going to fit without changing the hubs too.
Did I miss the reasoning for building up different axles vs just upgrading what you’ve got?
Have you actually looked that closely at a grenadier? Honestly, I think they’ll outlast stuff like that very easily.
Going back to a previous point on cost…. Farmer in the village has an 18 plate Range Rover he bought very nearly new. That does everything - dragging trailers about, plastered in mud permanently, boot full of sheep/cattle feed, bales etc. it’s still going strong with zero issues.
The point you’re completely missing is that the added quality over the ‘cheap’ pickups means they won’t be disposed of after three years for being ‘worn out’. They’ll more than likely still be going.
As for the mention of tractors, it’s a very valid addition. Forking out the money on something like that is done in exactly the same way as a grenadier would be - the business case. Greater value after 3 years means it will stay longer so the cost is much less relevant.
Reasonably so…. @NRS91 is the man.
5th wheel/gooseneck is able to have 3500kg on the trailer axles PLUS whatever payload the tow vehicle can take on the pin. So if you’ve got say 1.5t capacity in the bed of something like a 110 pickup, 3.5t for the trailer axles and you’ve got a trailer weight of 5T.
Some versions have electric brakes, some will use air.
Nick tagged above has a lovely mini artic on a 3.5T Iveco.
Roughly whereabouts in the UK are you? Only club I've got direct experience of is Shire LRC who are based around southampton, lots of very experienced drivers there who would happily show you the ropes. @FridgeFreezer and @miketomcat are on here.
Experience of rally and two wheels will be a massive help, as you'll be used to reading the ground.
Hitting the second hand market already! Local to me, utility wagon, 2500 miles. £50k+VAT
https://www.cornemotors.co.uk/used-ineos-grenadier-witney-oxfordshire-5658158