I had this very conversation the other day with my home insurers. They were happy to put my kit on my home policy but they had to be counted within my overal contents policy. So if my contents were insured for £100 and I told them my 17th Century Double Bass was worth £80 then the rest of my contents would only be insured to the value of £20. Obv, these are not proper numbers.
Sadly, I also need to rethink my insurance policies.