Phil Connolly up north who flies Huey G-UHIH has recently imported an OH-6A and appropriatetly registered it G-OHGA and the CAA data shows they are aiming for a permit for it as it will, like the Huey, only be flying for displays. At Heli-Expo it was confirmed he is getting a Cobra too..... Go to
HUEY.CO.UK and off the Welcome menu check "Our Helicopters...." for photos.
I would expect that's the nearest you will ever get to a non-US registered OH-6A flying in Europe. Not EASA/JAA certified, Permit only.