Well the thing is, those cleaners look very similar to many sold here today. In fact, most cleaners here now look very like another. To that end, I have long considered that our vacuum cleaners are all rolling off the same productions lines under different names.
The only time I was aware of a Zelmer presence in the UK was when the Rotel and Spinney names were prevalent. I've not seen it's kind since the mid 1990's. Rotel is a company in it's own right and a good deal of stores used to stock very inexpensive Zelmer cleaners with the Rotel name.
Spinney was a name which Littlewoods utilized on many, many products made exclusively for their chain of stores, presumably the name was taken from their HQ which was known as "Spinney House". One of the manufacturers which Littlewoods patronized was Zelmer, and the supplied a range of vacuum cleaners in typically either brown & beige or red & white. But Zelmer were not the only suppliers by any means; Goblin made cleaners for them for a short time, as did a few other lesser known companies.