OK lets say, using myself as an example 
I pay my insurance monthly with a seperate finance company who pay the insurer in one pop, lets say £100 month equating to about £1300 once the interest is added on , this would be on say a group 17 (old style) car.
Now then, if i was to change the car on the policy to something say of group 5 or 6, so roughly 2/3's less risk can I expect any kind of pro-rata refund in any shape or form?
I literally don't know what might happen in this situation , would it affect the policy in any way, ie stopping you getting a full years ncb by not having it accumulated over the course of the year on ONE car?

I pay my insurance monthly with a seperate finance company who pay the insurer in one pop, lets say £100 month equating to about £1300 once the interest is added on , this would be on say a group 17 (old style) car.
Now then, if i was to change the car on the policy to something say of group 5 or 6, so roughly 2/3's less risk can I expect any kind of pro-rata refund in any shape or form?
I literally don't know what might happen in this situation , would it affect the policy in any way, ie stopping you getting a full years ncb by not having it accumulated over the course of the year on ONE car?