Ascoteer is quite correct:
"These are NOT Dominies.
The Dominie was the HS125 Series 2 fitted with the Viper 301 engine and unique to the RAF.
These are the CC3 which is the HS125 Series 700B (and fitted with the Garret Turbofan). There are a number of significant differences between these and the Dom."
However, it didn't stop us ex-AEOps/Siggies calling them that when they helped out moving some stuff around theatre for us
Wasn't long before one of the crew or the old gent contractor groundcrew used to correct us - not sure they ever realised we were doing it on purpose...