The recent CHOGM in Malta had The Queen and Prince Philip travelling in a Titan A320 and Charles and Camilla in an Embraer Legacy. The TV coverage I saw also clearly showed one of the 32(TR) 146's parked on the ramp at Luqa (maybe this was Cameron's transport?).
Meanwhile various Commonwealth Nations sent their leaders in Govt. Boeings, Airbusses, Globals and Gulfstreams (checking this spotters list from the last few days
http://www.maltaspotting.com/aviationinmalta.htm).
We lead the Commonwealth, but not in aviation provision for our VVIPs it would seem :-(