Hello vacbear. Yes, I was mentioning the clips on the back of the tube earlier. It was around 1986 when Hoover reverted to a push fitting, this time plastic tubing, using it on the Spirit cylinder and one of the Portapower models. Although different in design from the cylinder tools, a 32mm push fit was introduced on all Total System Turbopower and Turbomaster cleaners as time progressed. From here, Hoover then ran two styles of tools, with the pip and rings being used on tool kits for upright cleaners which had separate tools, and on the more expensive cylinders.
The likes of the Galaxy which you mentioned, the Jet, Sprint, the Vouge, Aria, Arianne, Telios, and more all used this push-fit tubing, some cleaners even having metal tubes by then. I am not sure when the clip and ring disappeared altogether, but it was widely used across the Alpina range and as far as the Turbopower Junior went, they never did have push-fit tubes, only pip and rings. So I think the pip and rings were used well into the 2000's.