Thanks for replying ruby123 that's what I've been told by an mk3 guru yesterday and that what I have on the 1600i arb setup

So just to clarify my understanding

1600i rose joint n/s and o/s are left hand thread
S1 tie rod ends n/s and o/s are right hand thread

1600i and S1 arb ends at the tca are right hand thread

Mk3/Mk4 standard arb ends at the tca n/s is right hand and o/s is left hand