Red pustules on Sycamore leaf.
No interactions present.
It is my impression that this type of gall tends to happen in broadly the same location in successive years whereas galls from wasps turn up more erratically. I have been presuming that this is because mites don't fly whereas wasps do.
cheers. It's in the garden, so I can check if it recurs in future years.
Lat/Lng: 53.8, -1.8
OS grid ref: SE1540