I was dead worried about not having declared minor mods last year when making a claim (insured with Carole Nash). The only additions to the bike were heated grips, a hugger and a fenda extenda. I took the fenda extenda and hugger off before the insurance assessor came round, leaving the heated grips on and the chap didn't even bat an eyelid. Because it was my first bike policy I didn't even consider declaring them but got worried when it came to claiming. But all was ok.
When I rang up for a requote on my replacement bike and they said 'do you have any mods', I started saying 'Yes, a hugger, heated grips, etc,' and the lady just cut in saying 'not cosmetic changes, just performance enhancing changes', to which I replied 'No, no p.e. changes' and she said 'thats's fine then'. So I wouldn't declare any minor cosmetic changes unless I really wanted something specific covered (like if I decided to get diamond encrusted fairings or something
).
Bit of a long ramble, but CN (thus, I'm sure, other insurers), only seem worried about performance enhancing mods, and when they ask how much you want it insured for, just add a couple of hundred to what you think you could sell it for, to cover any minor mods.
/Deep Breath.
Cheers,
Matt