What if he was to drill new mount holes in the floor? Not 100% sure but would his problem not be the handbrake. I was thinking the shroud is part of the seat base or it looks that way on my Pug version of the Mk1
I got a single passenger seat out a Scudo to replace my Dispatch double. The base did not line up. I drilled through new holes and put load bearing plates under the bolts under the van. The front two bolts went through the factory load plate so it was not that big a job.
OP. How about looking to see if the Mk2 seats fit the Mk1 base.