I think they sometimes pluck the firgures out of a hat.
I rang my insurance company 1 month ago to swap the bike on my policy and they wanted ?525 EXTRA on top of the ?325 I had already paid, the sale fell through and it never went ahead.
I rang again last week to change the bike on my policy again for another sale and for the same insurance group bike, which is just a nippy and the same value.....?185 extra on top of the ?325 I have already paid.
So had I of done it 1 month ago the years insurance would have cost me ?850, where as now its only costing me ?510 for the year.....fully comp at 24 with 1 years NCD