Not having seen or heard any reports of Southern Emerald from this site in the current season I checked things out today and found their situation to be intact. When this colony was discovered in 2018 it was only the third known population in the British Isles (see here); the other, longer established ones being in Kent and the Isle of Wight.
This site (SU 96052 88958) to the south of Beaconsfield and beside the M40 motorway is accessible only on foot along public rights of way, and there are no safe parking places on nearby roads. The path I followed skirts a large landfill site before reaching a small woodland where it becomes less distinct. I had caught up en route with a weather front that passed through Oxford earlier, and upon my arrival conditions were quite overcast. But when the sun came out I began to notice Emerald damselflies that upon close inspection were indeed my days’s target (pictured below).
The most obvious feature by which Southern Emerald may be distinguished from other related damselflies is their two-tone cream and brown pterostigma (wing tags). In around an hour on-site here I located nine individuals including a tandem pair. The regenerating habitat was wild flower rich, and I dare say it supports many more of these nationally very scarce insects had I searched for longer and more thoroughly.
A year ago I was hoping they might expand their range from this location and maybe even reach Oxfordshire, but whether that has happened or not is unclear. Another observer I met today told me reports are indeed getting out on-line again, so we will have to wait and see.