"The Hawker Siddeley Dominie. Surely it was bought as the DH125?"
Hawker Siddeley acquired De Havilland Aircraft in 1960, the year before the 125 project was started. However the old legacy name and the 'DH' designation was used during the development phase of the project. After the aircraft went into full production (the first customer airframe was delivered in September 1964, the first Dominie XS709 'M' being delivered on 30 Dec 1964), the name was changed to 'HS 125'.
Sad to see them go, I really enjoyed my 1000+ hours on type.