In fairness it’s because it’s the only one I’ve done with a separate bell housing, which I put on first as the gearbox is much easier to line up and push straight onto 4 studs that fit with the bell housing and have to wiggle it up and in the the trans tunnel and try and reach around the gearbox to fit all the awkwardly placed bolts.
But by doing it that way you don’t go through the normal process of slipping the bearing over the input shaft while preparing the box to go on.
Thankfully I checked whether the clutch felt ok before fitting the prop shaft, heat shields, exhaust etc or there would have been even more swearing