Thanks Comms Boy and What Limits.
You have a good point there WL. It's all very well having the latest all-singing, all-dancing whizz-bang, super shiny piece of kit but if, when it breaks down / software repeatedly crashes etc. and the manufacture can't be bothered to return your calls, your very expensive investment is useless!
Comms Boy - It would be video and thermal imaging mostly, but some LIDAR. I know Rohde & Schwarz stuff from my flight calibration work and have always been impressed with it. Bit expensive though! The info about the DF gear is useful and much appreciated. Thanks.