There is no industry standard or rule that defines an "English" blend. In common usage, it seems to refer to a blend of Virginia, latakia and oriental tobaccos, and never aromatic. Of course, other tobaccos, such as Perique, can be added. Using the common understanding, and trying to avoid the sometimes-controversy over the use of the term at all (or trying to split the proverbial hair that distinguishes a Balkan blend from an English blend), one could make dozens, perhaps many dozens, of English blends. Dunhill, when it was a shop in London, made custom blends for many of its customers and would have made hundreds (perhaps thousands) of "English" blends.
The same basic ingredients, tweaked and handled slightly differently, can give a different end result, sometimes much different. Much like wine, Scotch, beer and bourbon. Calling a blend English is about the same as calling a wine red. It will be decidedly different than white, but beyond that doesn't tell you much about how it will taste and whether you will enjoy it.
Some define an "English" blend that contains Cavendish (unflavored, of course) as a Scottish blend. Not all agree, what would be the fun in that? By that definition, MM965 and Aperitif are Scottish blends. Somewhere in England, someone who smokes MM965 is infuriated that I have called his favorite tobacco Scottish. Such are the risks when we categorize things.
Historically, England had laws that prevented tobacco blends from having any non-tobacco additives, flavorings or humectants. Or, at least, greatly limited those. So, any blend made without additives, regardless of the type of leaf used used, could be called "English." Confused yet? Good. No reason why you should be any different than the rest of us.
Of the Dunhill blends, London Mixture is what I think of as a sort of base-line, iconic English blend. Not that the others are not excellent blends, but London Mix is kind of in the middle and will give you a good reference point as you explore these types of blends.