Clint-Green I don't trust the airlines. Even in full-on flight cases things get damaged - even if checked into the hold as carry on luggage. So packing as well as possible is key - I've pulled the neck off my guitar and re-assembled - pita, but it survived a bunch of flights!
Technically you are liable for vat + processing charge (14% plus +/-1%) when importing musical instruments. I'd just walk confidently through customs...if stopped, I'd say it's my instrument for a 50th birthday party gig I'm playing at for a friend. And yes sir, I keep all my instruments in showroom, as new condition. Nudge-nudge, wink-wink.
You are allowed a certain amount of personal import goods when you come through customs, not sure what the threshold is or if that includes instruments.
tl:dr : Declare it as a import and pay +/- 15% or stroll through and, if stopped, claim it's your personal instrument that you travel with.
