Hi Nigel,
I agree it looks vaguely Velocette-ish (if you ignore the "unusual" front fork), but I don't think it is. You'd have to be comparing it to the c1913 Model A Velo (the motor looks like a 2 stroke to me), and you'd find that the tank on this bike is very deep and that the magneto is mounted in a strange location: immediately in front of the cylinder. Velocette mounted the magneto behind the cylinder on their 2 strokes.
The magneto seems to be Ruthhardt/CAV, which might date the bike as 1913 or later. But the combination of deep tank, strange front forks and high-front-mounted magneto doesn't ring any bells.
The print looks to be of excellent quality: the best bet for ID might be a bright light and a magnifying glass to look for a name on the tank.
Leon