A subject of interest to all of us. I check others every year; after realising some time ago that loyalty is a foreign concept to insurers. This year a huge increase from SAGA, £650, reduced to £450 from Octagon (wife and I with 6points and a recorded theft loss claim; fully comp with bonus protection). The best In the past was NFL but that was when we lived in a 'nice' area, they won't even quote for our current locale; they are honest about their business strategy 'nice places no scum'
Other things: thoroughly check the paperwork (a friend of mine may be facing a total loss of £4k after his scooter was vandalised on his drive and discovered he was not covered for commuting, though he swears he put this in on the Internet quote)
Protected bonus? How does that work when the insurer can set any premium before applying a bonus reduction. It all makes you mad!