Yes I have... I first fitted 156 seats from a 4 door because that's all I could get at the time. They required homemade subframes with hinges to allow a bit of access to the back seats, not ideal and because of the subframes a bit too high for comfort.
I have since got a set of 147 3 door seats just like the ones in the top pic. A vast improvement. My car has the early seat fittings and the 147 seats are a very simple fit. The runners are exactly the same width as the Viva ones and there are holes in the runners that line up perfectly with the original ones in the floor. I made up some hardwood spacer blocks to level everything up and bolted them straight in
They are a perfect height and give great access to the rear seat.
Editor of the VVOC Magazine ReVival
"When you have a Firenza like mine, who needs any Minis?" copyright David Maxwell 1979.