Hi Glynn, i have had to get replacement valuation at current prices for my alembics from Mica because Allianz is an old for new policy. Allianz told me that if don't correctly declare the current retail price, in the event of a claim, they 'may not' pay out because you were under insured.
I would check the small print because whenever i tried to include my instruments on household item cover, which in the past were all well under £1k the clauses stated they are not covered if used for financial gain gigging, paid sessions. Hope yours doesn't exclude them. My Allianz cover this year was through the roof but i had to pay it for peace of mind, plus complete a security assessment form.