I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
You can park on the road very near to Brynich Lock and then it is a short walk to the aqueduct itself. Follow the canal leading away from the lock.
Presumably BWB or Canal River Trust as they are now known may have something to say about flying on their property, but be sensible, follow the usual guidelines and regs and all should be fine.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 30/05/2023. It remains the responsibility of any pilot to check for any changes before flying at the same location.