The top adjustment of the rear channel, which only controls how deeply the glass engages with the channel:

The lower adjustment - the 'external' screw controls the depth of engagement of the glass with the channel, the 'inner' screw controls how closely the glass engages with the door seal towards the upper rear part of the opening:

Make sure there is a gap between the rear edge of the glass and the B-post trim channel. This glass could do with being a bit higher, but the upper stop peg is at the top of its slot, and it doesn't leak:

There is a stop-bolt AHH7560 screwed to the inner skin with large washer PWZ205, spring washer WL6000051 (missing in this image) and nut FNZ205 which controls how far the drop-glass can be wound up: (British Auto Salvage)

Positioned here:

The bracket and felt pad (to prevent rattling, missing here) at the bottom of the door as a lower stop, seen through the rear-most hole in the inner skin. Note that replacement doors don't seem to come with this platform which is why it is available as a separate item (AHH7550/7551SSK) that has to be drilled and screwed. Also indicated is one of the three drain holes that should be present where the base joins the skin: MGE Experience

The three drain holes from underneath: