OK, I've got a can of Strongbow in front of me. The ingredients are listed right on the can.
Ingredients: fermented apple juice & glucose syrup, water, sugar, carbon dioxide,
acid: E270, E330, antioxidant: E224(sulphites).
That is way more information we get from other beers. MY gf and I compared Strongbow to my well aged Apfelwein. There are some similarities. Strongbow is stronger and drier/crisper.
Notice the "glucose sugar" ingredient. I suspect that strongbow has less apple juice than Apfelwein and more water/sugar, ie "glucose syrup". Once its fermented, they must stabilize it with potassium sorbate and then dilute it with water and carbonate it. We should be able to reverse engineer and clone it.