The St Aldhelms patch doesn't have a lot of obvious water and so it has a limited number of resident Dragonfly species. Over the recent few years of watching the patch, I've only seen six species of Dragonflies that I believe breed : Southern Hawker, Migrant Hawker, Emperor Dragonfly, Golden-ringed Dragonfly, Broad-bodied Chaser (only suspected breeder) & Common Darter. I've only see Large Red Damselfly, but Phil Saunders has also seen Azure Damselfly. I suspect that I would find additional records Damselfly records, if I could search some of the garden ponds in Worth Matravers or if I visited the Pier Bottom pools in the Spring. However, the latter idea is isn't particularly safe, given the soft clay cliffs are still wet in the Spring and more prone to mudslips.
Given the limited number of resident species Dragonflies, it is always worth checking any Dragonflies seen on the patch as it can also pick up migrant species. In recent years, I've seen Vagrant Emperor (found by fellow patch Birder Phil Saunders) & Red-veined Darter. Phil has also found a Norfolk Hawker, Four-spotted Chaser (a presumed migrant) and Small Red-eyed Damselfly. None of these migrant sightings have lingered for more than a few photos for either of us.
I've often wondered how Dragonflies see the world with these superb eyes. This BBC Senses clip on youtube provides a fascinating explanation of how much better their eyes are at processing motion than our eyes.