Wing span approx 7 to 10mm. Small silvery flies with blue or greenish sheen(?) Antennae curve outwards. Flying close to water surface.
No interactions present.
Are they flying or stuck in the water surface? They look like moths or caddisflies to me. I don't think mayfly wings would be so opaque.
Lat/Lng: 55.2756, -3.8207
OS grid ref: NX844994