I’ve created enough space without removing the whole seat from the van, got about 6’8” measured from the bottom of the tailgate window to the loose cali seat back.
This involved partially stripping the seat and lifting it out of the rails at the same time supporting on scrap plywood with bubble wrap cushion between flooring and ply. The seat was then slid as far forward as possible before securing with a ratchet strap to the passenger captain seat base.
It’s possible to do with one person as you can stand in the middle of the seat with the cushion and drawer removed.
Steps required;
A) Remove that additional wood conversion trim on the nearside and back (If fitted)
B) With the drawer open pull the bottom of the plastic trim above the drawer front forward to release the fir tree clips, just need to lever it out to access the 2x bolts each corner to allow the seat base cushion to be removed.
C) With the seat base cushion removed and the drawer fully open there is easy access to remove the 4x screws per side on the drawer runners. The drawer and runners can then be pulled forward and removed.
D) Remove the rail covers and slide the seat to the correct position for removal.
At this point I probably could lift the seat out alone but I would opt for two people.
I also thought about putting a cushioned beam (4x2” wood) across the opened pop top frame and use my 0.5 chain hoist, this would still take two people, one on the chain hoist and one to pull it out of the van.
I had a good look at the seat back hinges with a view to stripping the seat back off, decided that was not a good idea.