Hello Michael,
I am sincerely sorry to hear about your continuing story of woe with your Alphie.
With the greatest of respect, I think your accident record is the issue with insurance.
Without doubt insurance premiums have risen.
But I have read, in this forum, of many members who have received increases but not by much; including myself.
I was insured with Aviva for a very reasonable premium until I have my van converted.
When I informed Aviva of the 'modifications' they asked me to find another insurer and gave me a reasonable time to do so.
I hope that another year will give you plenty of time to find another insurer; perhaps you should try not going through your broker.
Try LV, they have several subsidiaries that do insure Alphards.
Good Luck, and hopefully enjoy a years motoring in your Alphie.