mondeo 3 seat bench

Also I believe altering a vehicles seating capacity requires a VIC inspection and MOT. I'm sure too that the seat belts etc have to be new ones and that the mounts have to be shown after welding and then the completed car presented for a full inspection.

Sure I saw it on one of those male your own car type program's. I could be wrong but sounds likely.
 
No good for car seats. The void under the bench that accommodates the buckets is still there. I'd never put my child in a car with half arsed seating.

True - I found a rolled-up fleece blanket placed under and behind the child-seat to fill the bucket and a seat-belt tightener does the trick though: http://www.amazon.co.uk/exec/obidos/ASIN/B000056JHP/ref=ox_ya_os_product
With this you can take up all the remaining slack in the seat-belt once you've tightened it, making the child-seat utterly immovable. As the seat belt gradually slackens off by stretching or climactic conditions, you can tighten it another notch or so.

As to the bench-seat mod, having had short adults struggling in the back, I doubt anyone other than dwarves or small kids would fit in there as their heads would be brushing the roof - also wouldn't their legs be jammed into the backs of the front seats without the buckets to lower them further back? My wife and I are both 5'11" and my seat is right back: hers is slightly forward to accommodate Katy's legs on the child-seat and her knees are consequently pressed against the glove-compartment. She hates travelling back to UK in the Cougar...
I already have a smaller booster-seat on order for Katy for when she turns three and so can sit 'further back' in the back, using the fitted seat-belt with an adapter instead of the huge child seat.