Alternator differences.

[chewbacca]

Can’t get my head around your photo, but I’ll post this anyway for reference.

That photo is really handy actually, I couldn't decide if there should be a nut between the alternator bracket and dip stick tube. Obviously not.

[Oldiebut goodie]

To tighten pulley nuts I use an old belt round the pulley and hold spare length of the belt in the vice - you can get a fair amount of torque before it slips. Saves damaging the pulley edges trying to hold it by other means.

[chewbacca]

I'll give that a go. Not sure how well it will go with no key on the pulley, but there's 2 chances.

[Oldiebut goodie]

A gentle tap on with a hammer usually suffices to get enough grip. Pillar drills use tapers without keyways for the chucks and they don't move.

[Mocki]

Once it’s on, and the alternator belt is tensioned you can give it a final tight against the engine resistance with the van in gear , handbrake on 

[DoubleOSeven]

Dipstick is held by a clip to this tiny bracket.

I'm not 100% the early DG's had the cross brace - ref. '12A', but I'm sure someone here will know.

[ZsZ]

45a uses a flat adjuster 
65 & 90a use a kinked adjuster

no idea why

came across problem when i upgraded from 45a to 90a

Probably the bigger amp pulls harder on the securing bolt so you need to tighten it more which needs longer thread in the alternator.
And Bosch had that shield in stock so VW had to adapt. 

[chewbacca]

Dipstick is held by a clip to this tiny bracket.

I'm not 100% the early DG's had the cross brace - ref. '12A', but I'm sure someone here will know.

I have the bracket, just couldn't remember how it went on.

[DoubleOSeven]

Just use one of these if you get stuck

[chewbacca]

Made the alternator fit.

[chewbacca]

Quick update... 
Crank pulley, water pump pulley & alternator pulley all line up! Just need to tighten all of them up at some point. 

Thanks for al the help guys.