I walked along the south side of the middle reservoir, and managed to see a total of 4 Peacocks, 3 Commas and 3 Dark-edged Bee Flies.
Dark-edged Bee Fly
Along with these three species, I also managed to spot my first species of hoverfly, a Drone Fly (Eristalis sp.) , and a bee species , which may be some kind of Mining Bee. I'll update if, and when I manage to get a proper identification.