My parents had the seats retro fitted a couple of times in the past with their Volvos - Volvo dealers did it - can't see why it wouldn't be possible any more.

It is possible and not actually very difficult. The main difference is that a factory conversion has an extra inside release on the tailgate which aftermarket ones usually do not.

Once again - thanks all. Looks like it is a goer if a factory 7-seater D5 doesn't show itself.

Really nice cars btw, Was mightily impressed by a 145k mile slightly scruffy '53 plate last week when I accompanied friend on her test drive. Excellent exhaust note from the 5 cylinder diesel, loads of urge and not a squeak from inside (although valet would have been good!).