Got this info from Aussie Vintage Vacuums in Australia
Newmaid were making frictionpowered vacuum cleaners from the early 1930s and were based in Northampton.
They made these vacuums until the early 1950s.
This model may be from the 1940s the bag being plain unlike the 1930s with the black striped cloth with instruction booklets fitted into a pocket at the rear of the bag.
The primary use of newmaids was on cruise ships where electric power points simply did not exist back then.
Hope this helps
All the best Graham