I first noticed it hovering around a verbena bonariensis plant in the forest garden, but ti quickly turned its attention to a flowering buddleia. In fact I had plenty of time to phone Sue and drag in the house to come and see it. Occasionally it darted off, presumably to another feed plant, but it kept coming back to these same few flowers.
It was impossible to get a picture with my phone. The things never stop moving and even if it did pause long enough, the wings just make the whole thing a blur. So I decided to pick one flower and wait to see if I could shoot a bit of video. Actual views were much better, but hopefully the video I've attached: 1 - works and 2 - gives a good general impression of our visit.
So if you've any suitable flowers in your garden, workplace, local park, wherever, then do keep an eye open and you might just be lucky enough to meet one of these little fellas.