That's a good piont Dodgeman but then there are intances where it doesn't work.

Take this example of my Dads' friend who was restoring his old sliding window mini. He canged the doors to the newer ones and mounted seatbelts onto the B pillars where you would normally and when he went to get it registered it failed because of the seatbelts. They were not designed to take the strain of saetbelts in that section.

I know it's just me rambling on here but some of it is legit