YES. Brides in the Volvo. Correct.
I ground and drilled the mounts off the original rails and bolted them onto the new rails, I'll weld them when I have access to a welder, but that was basically it. OK, it took a lot of thought and planning, but it was actually pretty simple to do once I had it all figured out. The micra doesn't have anything wired to the seats or belts which makes a BIG difference.
The mounts are all pretty tough steel, so you've got to take your time. I had to drill out rivets on every mount, starting at 2mm and working up to 8mm, stepping up 1mm at a time. And I still snapped or blunted a bunch of drill bits. I also used about one and a half cutting discs on the welds.
Costs: Seats £30
Nuts and bolts £4
Cutting discs £5
Snapped a bunch of drill bits..... so £20
I also bought a couple bits of cold rolled steel from B&Q, but I didn't need them in the end, they cost about £6 per metre.