This snapshot and grainy crop might not do the bird justice, but they do record what I foud to be a surprising sight.
To see a heron sitting a few metres behind Wightman Road still has the power to give me a nice surprise. (Though it's odd that he was more interested in the goings-on of the WIghtman Road gardens than in finding his lunch in the river.)
I live on Wightman Road and my neighbour has often seen the heron on our garden fence, I haven't been lucky enough to see it yet.
If you walk along the path between Wightman and Hornsey station, the heron is often sitting on the far bank, although it usually flies off (in the direction of the trees above the weir) as you approach.
I would say that structure is a vent for the Piccadilly line tube!
I think it's about a quarter mile away from the underground. So I don't think it'll be related to that. The air shaft for the Piccadilly line is on the corner of Colina Road and Green Lanes, next to the recently demolished Oakwood Laundry Building.
There have been a couple of discussions about this before. See this page and, in particular, my link to another thread about half-way down. In that other thread, Dick said that he was told may years ago by a New River maintenance man that it's a vent and access to a storm drain which isn't related to the New River.
Sorry, not sure what you're asking. Do you mean to ask whether you can access the tower from the premises of the car repair business? I'd imagine, whether or not the building is accessible, it will be firmly locked. Are you hoping to go and investigate?
Oh, no, I'm not so adventurous. I was just wondering if there were clues that the tower was actually once used for access.
Shame - I thought we were going to get some photos!