I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
There is no parking but there are side streets a short walk away towards Turners Hill village.
The fields in front of and to the side of the reservoir are on a public foot path which leads in to the woods themselves.
There is some low level electricity pylons coming from the right hand side of the reservoir that extends through the public field and beyond.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 26/03/2021. It remains the responsibility of any pilot to check for any changes before flying at the same location.