Ken,
Not sure where the confusion is.... maybe because Robin stated that Gloster's are not a colorfed canary? Her statement was the 5th one down in this post.
To clarify, breeders wanted a creasted red bird so they set about to creat one. They took glosters and red factor canries and crossed them until they got the conformation/color that was desired. They then set a standard for the breed and deided to call it the Stafford.
There was a bird in Europe already called the Deutche Koife. This was a red bird with a semi crest. Breeders worked to get the crest improved and was recognized once perfected as the Stafford in 1987 and was cosider a new breed of canary in Great Britain.
They then became quite popular and spread all over the globe.
Some breeders still do the origional crossings of red factors to glosters. Though these I call red crested birds or red factor glosters hybrids because that's what they are

They are fertile though and not like mules of different species.