There are to many people saying what we Can and can't Shoot ! I had a similar experience a few weeks ago at Heysham port, I was told by a private security firm that I wasn't allowed to take any pictures because of the nuclear power stations opposite, My reply was it is a public right of way And I don't take pics of concrete blocks, He was not a happy bunny and asked for the port police to come, This guy was great asked to see what I had taken then told the private bloke to stop wasting his time.
Mind you I had been testing my 300m lens so it may have looked a bit suss
regards Ian