Speedy reply from Philip!
Yes this is certainly the ex. Custom’s Watchful.
She was a steel, Steam Launch, 52ft x 12¼ft, 41.5 tons Displacement, 20grt, 77hp, 8½kts, and as you say Edwards & Co, Millwall, 1908
She was sold out of service 4/1939.
In the 1960’s she worked as a yard launch at Tyne Dock & Engineering Company.
I have no idea of her final fate.
Page now updated
http://shippingandshipbuilding.uk/view. ... l=WATCHFUL