I find these insects extremely interesting. living in Hampshire is a dream where these insects are concerned. I am reasonably close to Thursley common (Surrey) 30mins drive, the New Forest is 30mins drive, and Warren heath is 15mins drive. I have been photographing Odonata for 4yrs. my current go to gear is a Canon 7dmk2 and 3oomm L series f4 is lens. along with a Canon 650D and 100mm L is macro lens for closer work. The only downside is the weight!  I take a spare battery and memory card for each, along with a bottle of water and an apple happy days!  I am currently trying out OLYMPUS Gear, the size and weight are a real treat. I use an EM1 with 40-150 pro lens and an EM5mk2 with a 60mm macro lens. At this time the only drawback is  dragonflies in flight. the olympus is what is called mirrorless and there-fore employs an excellent EVF  this type of viewfinder is electronic and what you see is a split second behind what is happening in real time! I have managed a few good images of DIF (Dragonflies in flight) but the keeper rate is far below the Canon set up.
I have found and used these books to be of interest
Britains dragonflies
by dave Smallshire and Andy swash.
Dragonflies of Britain and Europe
by Dijkstra.
Field guide to the dragonflies and damselflies of Great Britain and Ireland. by Steve Brookes and Steve Cham.
             OTHER WEBSITES
Hampshire dragonflies
by paul Ritchie.
Chris Brookes photography 
UKDragonflies  forum
British dragonfly society.
                                Please checkout the books and websites below which are great!