Posted: 29/02/2016 at 08:37
Could they be cockchafers (also known as May bugs or June bugs) . Amazing creatures - we love watching them. Although ours fly high in the treetops, not low around the lawn.
Many years ago when there were swarms of them they were seen as a pest of farm crops, but nowadays there aren't so many and they do very little damage - it's such a shame to kill them - they're part of the wonderful world of nature and an important food source for bats.