For anyone out there who has a classic, (up to 1970's) try Footman James. They did me a could deal on my Norton, 50% cheaper than Carole Nash for the same cover.
For the last 3 years I've been with Peter James for my 3 classics insurance and they even tagged my '13 reg Tiger onto the policy. They gave me the best deal . Mid term adjustments with Peter James is under £20, can't remember the exact figure. Unlike some who want to charge over £50