The clue should be in the chainset design. Cottered cranks chainrings were often cut to the design of the manufacturers logo. Raleigh features the heron head, Rudge has a hand, Phillips says its name etc.
The fork crown is also often a clue, the bike in questions crown is reminicent of a Rudge but they tended to be chromed, this is not. The photo does not allow a good veiw of the headbadge which is the most obvious clue. Somebody in the know tell us, I'm intrigued