I’m by no means an expert on Scott history but I believe that the original “Flying Squirrel” or Flyer of 1926/7? had a tank transfer that portrayed just that, a “Flying Squirrel”, with its “wings” extended and in flight. Nothing like the little creature on which these mascots are modelled which looks to me like a standard British red squirrel. If this is correct then the mascots could well be unofficial.
However, just to add to the confusion, I’m certain that the B’ham Scott that my father owned in the 60’s was registered as a “Red Squirrel” in the log book. It had the brownish red tanks & mudguards seen on some examples of the Birmingham model. Matt Holders idea perhaps?