Miniature anythings are usually medically less sound.

I am not aware of any breed properly called the "English Shepherd".

The ubiquitous working sheepdog in the UK is the Border Collie (only recently recognised as a breed for show purposes).

The Rough Collie (think "Lassie") and Smooth Collie (the subject of some argument over whether it is merely a coat variation or the last surviving remnants of an older working breed, the English Cur) are not really fit to work in the "One Man and His Dog" style. Generations of breeding for those narrow heads has resulted in dogs nearly as stupid as Otterhounds.

The Bearded Collie I think used to be a truly working breed, but I have never known of any with the instinct.

The Old English Sheepdog (Dulux Dog) is not a sheep-herding breed. It is a guarding breed that could be left in with the flock and a wolf with poor eyesight and no sense of smell could mistake it for a sheep and come to an untimely end. Do not think of them as fluffy and lovable - some are but many are not.