There are a few pointers I can offer. The first is to confirm the way that it will be described by the exporter. I imported a production station from the US to the UK a few years back. The production station is essentially a Windows PC with a few extra controllers including a 61-note keyboard. If I could have got them to ship it as a computer, I seem to recall that I would have paid less import duty. However, they were unwilling to do that. They shipped it as a synthesizer.
However, I don't thing there's much choice here. It's an electronic musical instrument. I think I started with this reference: Trade Tariff
I remember I did find someone knowledgeable to speak to by phone. I've tried to remember or track the number down; but no luck. If it comes back to me, I'll put it here. It might have had something to do with the Chambers of Commerce.