You are totally right, they were all glancing blows rather than total thumps, a bit of motorway ballet and gather at the side. I was joining northbound from the M3, and the M25 traffic was slow and luckily not too heavy, but the joining traffic was accelerating and jockeying for position.
I dread to think what the insurance co will be like it's just a normal, no agreed value policy. I've been meaning to change it over to classic car insurance for a while but you know it's always 'next time'.