Ovipositing on the underside of a sycamore leaf
No interactions present.
There are two species common on sycamore. The more common species is Drepanosiphum platanoides. However it has a more pointed cauda than those in the photo and it has quite long siphunculi which would be visible in the picture.
So I am inclined to think it might be Periphyllus. It would be to have a specimen or a picture of Drepanosiphum to compare.
I'll have a look around to see if I can find any. They should be appearing soon.
If you look close at the little white objects you will see that they are 1st instar nymphs. You can just make out their legs.
Lat/Lng: 52.9, 0.9
OS grid ref: TF9842