The two examples pictured carry dates on their motors the one above is 1922 and one below is 1921 - they have double cab windows with flared boilers. The 5 was the cheapest clockwork available at the time, it had no brake.

This one is missing the spring but has a 1924 date on the motor plate.

This one has a 1917 date on the motor. but it has cast wheels and had a drive rod. This would be like a No. 6 from that period