These are almost certainly going to be the Common Green Lacewing - Chrysoperla carnea. I say this for two reasons: first because this is the only green lacewing we have that hibernates in the adult stage and at this date it is unlikely to be any other species. This is supported by the numbers - one or two odd examples of other species might be encountered, but not 150. Secondly, because this species also migrates to Britain from Europe and there has been a good deal of recent immigrant moth activity ... So adding two and two ....
C. carnea is actually 3 species now - but 95 percent will be the true carnea, 5 percent will be C. lucasina and if you find the third species you already know its name but will still need to convince me (though there are 2 Essex records).
Lacewings are rather poorly recorded in Essex, though there is a provisional list in the Essex Naturalist (Snake-flies, alderflies and lacewings (Neuropterida) and scorpion flies (Mecoptera): a provisional review of their status and distribution in Essex with notes on their etymology. Essex Naturalist (new series) 18: 177 - 217, published in 2001).
I will be happy to name (or confirm) Essex lacewings of all kinds if sent to me as long as they are accompanied by (as a minimum) the capture date, the captor's name and an identifiable place name (ideally a grid reference as well, please). If return postage is provided I will return them, but I get many many packages each week so if it isn't I won't (unless we have an agreement in place). Non returned material will be added to my collection if suitable or binned if not.
Most lacewings can not be named from photos - though if I can I will.
Finally - the National Lacewing Recording Scheme is being re-launched this autumn - assuming I get time.