As always, great pictures. I would be prepared to stick my neck on the line and say that these Multi shampoo cleaners were out a on sale a bit before 1985, under the Aqua Vac brand, though I fully appreciate that the dates of your pictures indicate that the brown cleaner was later, as it ran alongside the Goblin in white.
The brown one is the version I've seen the most of. Around 1985 Goblin was bought up by a company called Shop Vac, who I think is of American origin and were the ones who were behind the Aqua Vac cleaners which originally went on sale in the UK. They also made wet & dry cleaners for other brands too, like Hoover. Now you will see in those pictures that even though the canister wet & dry machines are being sold as Goblin, they are still the original brown & gold, with original brown Aqua Vac tools. This colour scheme is consistent with that of the upright Multi cleaner and after the acquisition of Goblin, the cleaners were produced in black & gold, with black Goblin tools. It was around then or shortly after that the brown Multi cleaner became discontinued, though I have a notion it was not exactly a popular cleaner to start with. As well as using it with a plastic shampoo container, there was also an option of fitting a can of Aqua Vac aerosol foam to the cleaner.
Also around this time, the same machine as you Philips was on sale in brown & beige, under the Kenwood name. There were two models, a standard and an electronic.
