Flight aware at 1.31 shows it dipping to180m over the fort area. The ground is 110m there having risen from the direction it came so it could have been a little bit less than 500' above the buildings if flight aware is correct. At 230mph, that seems like a risky bit of flying for a private aircraft which would normally attract the attention of the enforcement department of CAA. Of course, if it was a test of the low level capability of ASWE, it was probably all above board. I see that Wincor in Liechtenstein are in liquidation - are they the real owners?