H500
Hi Sav,
I don’t have any information on EI-AUA but it seems Dennis Ferrantis EI-ATY was Trans World Helicopters first Hughes 500.
From Flight International 28 April 1966
“Trans World Helicopters are also interested in selling the machine (H300) to private customers and are looking forward also to the delivery later this year of the first Hughes 500, the civil version of the -OH-6A, although the first demonstrator expected in the autumn will be the military version.”
http://www.flightglobal.com/pdfarchive/view/1966/1966%20-%201246.html
Flight International of 24 July 1969 records this first machine was EI-ATY which had just arrived in the country.
http://www.flightglobal.com/pdfarchive/view/1969/1969%20-%202485.html?search=trans world helicopters