They didn't have electricity in Collingwood when I lived the other side of the Hendon Way.
Assuming its the ring aerial, ignore the telescopic bits, they're for radio, and aim it down the Edgeware Road, towards Croydon, i.e with the ring at parallel to the North Circular. Radio waves and brickword don't go together too well, so see if you can aim it through a window, or sit it on a window ledge.
Digital is a sod to set up, as it either works or it doesn't, and if it doesn't, theres not a lot you can do. I take it that you got as far as scan, but it can't find anything