Hi
to reply in order
1/ The calliper connection and chassis mount all that are required. With careful positioning of the flex in the chassis mount it is possible for the suspension to move freely without the flex contacting either body or suspension, which is what the IVA tester is looking for. If you have problems, or need another routing than the norm, just clip with a tie rap with a rubber spacer. (as per MikeD's pic)
2/ Chassis numbers must be 17 digits long, they can be made up, but must be unique to your vehicle. you can use your name, age, model, pets name or combination, as long as its 17 long. it must appear on your chassis plate, along with axle weights, build date etc, AND on the chassis itself, either stamped in the metal or in a plate WELDED to it.
3/ How old is your kit? the mounting changed over the last few months. the earlier one used a vertical bracket on the exhaust, which used two bobbins to mount to the side of the body. the later has a horizontal mount, and uses one bobbin to mount to a bracket that in turn is mounted under the side of the body, so no holes in your panels.
4/ The alloy seat rails have a tendency to bind when tightened down, usually caused by the seat mounting points. however if they move freely when bolted to the seat it must be the fitting to the floor, try to space them away from the carpet. The later steel type do not have any such problems.
On my many visits to the Nottingham IVA I have never seen the adjustment checked at full forward position, only full rearward. Will have to ask testers when they are open tomorrow. it is allowable to add extension plates to the mounts, provided they are up to the job. If you are able to correct the above, make sure the belts will still adjust. nice new belts stored in damp garages, or rained on whilst driving or transported to IVA, will jam.
Not in a position today to provide any pics, but if you need anything further I will try to help.
Regards