Hi garyh,
As well as the floor-pans you also need the repair section that forms a step in the corner and has the mounts on the bottom. This then needs to be shoe-horned between the bulkhead and the floor-pans.
Can't remember the technical details but the photo below hopefully makes sense.
forum1.jpg
These repair sections are (only?) available from Chic Doig in Scotland who has an Ebay shop and provides excellent service.
Hope this helps.
Chris