Hi Ram Man,
I've not long left the Army myself, after doing CP for a bit i wanted to open my field of expertise slightly so i decided to do a surveillance course. Could i suggest you do the ISS 10 day advanced surveillance
Surveillance Training - ISS Training Limited found it very informative and very worthwhile, the guy running it has years of experience within the military and commercial sectors. If that doesn't suit you i would advise shopping around as there are some dodgy alternatives out there.
Good luck.