4) With 35 or more body segments, always cylindrical, often with coloured spots?
You have an example of a
Cylinder Millipede (Julida)
Cylinder Millipedes are the familiar long cylindrical millipedes. They can have 50 or more body segments, bearing 100 or more pairs of legs.
Brightly coloured spots on the sides of the body are defensive glands that secrete noxious chemicals to deter predators.
About 30 species are known in Britain. (LINK)