The Excelsior was manufactured in the 1930s at a time when many companies were competing in the market. It is no surprise that designs from different companies often looked the same. The basic layout of the lawn mower design was already well established and as the use of materials began to shift from cast iron to malleable castings, plate steel and alloys there were only so many variations that designers could come up with.
Despite this, the similarities between the Excelsior and (in particular) the Qualcast Sixteen are striking: both have flat, cast iron side frames; both have a clutch mounted on one end of the rear roller that is activated by a thin rod running through the middle of shaft and pushed by a lever at the other end; both have the same Villiers engine; both have cylindrical petrol tanks mounted above the engine.
The Excelsior probably pre-dated the Qualcast Sixteen by a year or so although there is no suggestion of the later design being a copy of the earlier one. However, Qualcast with its superior sales network was able to promote its products much more effectively and the Excelsior sold in much lower numbers. Surviving examples are as a consequence relatively unusual.