I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
There is dedicated parking both at Harlaw Reservoir and nearby Threipmuir Reservoir. You can walk around the reservoirs or up into the Pentland Hills. Note there are nature reserves nearby so watch out for nesting birds etc.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 02/01/2024. It remains the responsibility of any pilot to check for any changes before flying at the same location.