I am insured via Victor C Knight. There are different levels, e.g. inside the house, anywhere i UK (inc left in a car) or worldwide.
I tend to add the EU/worldwide on an as needed basis, but if you were in and out of the UK for 10 months it would be best to cover for EU for the year.
As you have a BA alto, I would check that if in the case of loss the company will pay you market value cash for a "vintage collectible" as opposed to just replacing with a new Selmer,which might not be what you want.
This is part of the reason why I stay with Victor Knight.