No, but it always seemed an, "all eggs in one basket", type of situation to me. Does the whole group have to leave for a new insurance company when the excessive renewal quote comes in ?
Sheila's Wheels do multi car. I have never used that facility as I only have the one car but I have been a customer of theirs for many years, they always come up with a good quote and yes I do check, and are very helpful and efficient to deal with.
LV......(I have my home insurance with them - very competetive and doesn't keep going up....this year went down slightly!)
Here's a link for multi-car cover....