Saw an article on BBC "Look North West" tonight that explained a lot.

A week last Friday a Huey went directly over my house at about 300ft. It was only the second Huey I have seen in the UK ( the last being during a snowstorm in 1994 near Merseyside, I never found out where it came from ). The rotor slap though last week could not be mistaken as it approached

The BBC Tv article tonight explained that a guy in Wesham ( near Blackpool ) has brought a UH-1D over from the States, has assembled it and is now flying it himself around Lancashire. He intends to use it for charity events and for airshows throughout the UK. It also seems to sport ( de-activated? ) M60 machine guns at the door gun positions.

More on the above ( always pays to search the web first!!)

It seems it is an "H model not a D.

for more details see    http://www.huey.co.uk/index.php