From the article I was reading to accompany yesterday's Prince's Lane wander:
"In the 1970s, access to Prince’s Lane from Hotwell Road was walled off, and a gate was put in the wall on Hinton Lane, which was locked and prevented people from using it."
I think this is likely to be that gate. It's certainly close to the most likely path for Prince's Lane to shimmy between the back gardens of St Vincent's Parade and the back gardens of Windsor Terrace to emerge from the Clifton hillside onto Hinton Lane, anyway.
GPS Coordinates:
51.45085, -2.62476
Location: Hotwells