UKpaxman,
The paint scheme on that Viscount seems to be much more like that of Alidair and from what I've managed to research Air 'Danglia' only ever operated one Viscount which they leased from BMA in 1973 for a short time. I used to fly from Aberdeen to Sumburgh quite often in the Alidair Viscounts when I was based on the Brent in the 1970s and in the Air Danglia DC3s when I was going up to fly the Bristow Sumburgh S58Ts. I think the other airline operating them was Skyways Express?