This is the kit I installed on the passenger side of my 2003 v40:
http://www.ebay.co.uk/itm/Original-V...53.m1438.l2649
I think your link is the same. The kit is 2 brackets, you'll be taking out the seat backs and replacing the outboard seat back attachment/hinge with one that has an isofix bracket incorporated. Depending on which side you're fitting (drivers or passengers) the other bracket is either a replacement hinge or just a bracket that fits over an existing bolt. EG on the pasenger side the 2nd bracket fits halfway along the 2/3rds split seat back. Hope that makes sense?