Daytime small glinting orbs flying in formation in Horsham, UK

I got up from working and went into our kitchen to get a snack. I was washing a nectarine in the sink when I looked out our kitchen window. At first I thought there was a garbage bag flying through the air about 200m due east from our flat. Then I noticed that there were 10-20 objects all flying in the same direction. They flew in straight lines from south to north and stayed in a kind of random formation, not moving relative to each other. They were small white/gray spheres. Then I noticed about half of them were either intermittently glinting in the sun or emitting light, I wasn’t sure. All of them looked iridescent green like the back of a fly in the sun, except for one which shone/glinted red. The whole sighting was probably 10 to 20 seconds before they traversed my field of view and/or disappeared behind rooftops and treetops.
 I pulled out my camera and managed to take two pictures, in one I captured about 5 objects and in the other only one. I then tried to film them but something went wrong with the recording and although you can hear my voice the image is frozen which is a bit weird. The images are from the last half of the sighting when I got my wits together enough to try to get visual evidence.
 It is possible that these were drones but we are close to an international airport so I don’t think it would be any professional drone pilot operating these. Also not clear why there would be so many flying in a random formation. Thus I actually think these were proper UFOs/UAPs – my wife a glowing orb the same section of sky at roughly the same distance in the middle of the night about two years ago for whatever that’s worth.
 As for my bona fides I have two engineering degrees and a PhD in neuroscience and don’t consider myself prone to flights of fancy nor was I hallucinating – I was working at the time (unless coding triggers hallucinations). While I don’t have any firm beliefs on what they actually are, I do believe there is ample evidence of UAP generally. I would characterize my sighting as a typical orb type UAP report.