Leith docks?
No, it’s in England
Widnes ?
irlam
Neither of those. Father would know it !
It’s impossible to see from the road/shoreside as it is painted on a wall which faces the Thames stretching all the way from near Grays to just around the bend in the river before the bridge at Purfleet. Some of the artwork is really good, very good in fact. Bit dull when I took the picture with a 400mm zoom lens.
General location: Great Britain.
Close enough? 
Seeing as it’s you Orys, yea, close enough 
I am just strictly following instructions