Are the mites harmful?
No interactions present.
are those some sort of parasitic mite atatched to it?
I can't identify the Harvestman but red mite larvae are a common sight attached to many harvestmen. They cement them selves in place, dig their mouthparts into the harvestman host and suck on body fluids.
Lat/Lng: 53.03321, -1.59294
OS grid ref: SK273485
Rough grass, ungrazed. Surrounded by woodland and fields.