Thanks for all your responses guys. I now have more information myself having been able to speak to the technical staff operating the cameras.
Surprisingly I was able to get right up close and look in detail at the aircraft and installations.
The aircraft are Chinese Navy owned and flown, though in civilian uniforms. They have been painted in the 'Look of the Games' colours. The paint job is pretty rough and ready (over-spray on the transparencies etc.) and the camo-seats and drab harnesses are a dead give away as to the origins of the aircraft. I assume that the deck-lashing eyes are only fitted to naval varients of the type!
I rather got the impression that the guys running the cameras wished they had more experienced aerial filming guys up front.
The endurance is not actually adequate and the aircraft have to return to their operating base for a refuel halfway through the detail. Why they don't have a bowser at their forward operating base in the Olympic marina seems to be a mystery to all concerned.
One aircraft is fitted with a Scorpio Ball. Basically a standard shoulder-mount HD camera fitted into a gyro mount. Nobody seemed to have very much good to say about that one.
The other aircraft has a Cineflex Gyro unit which as discussed above provides some security entertainment. The unit is not allowed to overnight on the Chinese navy base and has to be fitted and removed each day. It is allowed to go back to base for refueling but only on condition it is under watch at all times.
The footage goes via a direct microwave down-link. This link seems quite robust, but the ones from the various boat-mounted cameras are very flaky. There is some speculation that this might be due to interference from military radar.
