I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
Thelwall Viaduct is a major bridge of the M6 across the Manchester Ship Canal adjacent to two discontiguous segments of a SSSI (Woolston Eyes).
Access is via a footpath from Thelwall.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 29/06/2022. It remains the responsibility of any pilot to check for any changes before flying at the same location.