not sure of the beetle or the small mites that seemed to be unwelcome, but perhaps were juveniles?
No interactions present.
Larger beetles quite often carry these mites - which seem to do them no harm. Your specimen looks like one of the Carabus ground beetles.
Definitely a nasty infestation of mites. Young beetles have a larval form.
Nick Upton, naturalist and photographer.
Lat/Lng: 51.121, -0.095
OS grid ref: TQ334374