I am used to buying wheat flour in France. I go to supermarkets/superstores and to organic-food stores.
In France, wheat flour is categorised by "extraction rate" (I'm not sure I'm using the right words, but it means how close to the core of the seeds the flour comes). For instance, T45 is very white, while T80 is more brown and there are T110 and T180, one of them must be wholegrain flour (there is nothing above T180). In supermarkets, the cheapest flour is T55. For cooking (e.g., for sauce) and for pastry, people generally use T45 because it's more "fluid" so it's easier to avoid lumps. For standard bread, it's T55. Then, if you want to have healthier (provided it's organic) flour or if you want to have a stronger taste, you can buy T65, T80 up to T180 flour.
Then if you want to buy spelt flour, you also find different extraction levels, well, maybe one or two different levels, provided that you find any spelt flour (it's easy to find in organic-food stores but elsewhere it's very unlikely to be found). Of course, there're many other cereals.
Let's go back to wheat flour. In the UK, you may find
Well, strong and very strong wheat flour are supposed to be made from durum wheat. "Normal" wheat flour is supposed to be made from common wheat. It's not that clear. On the package, the ingredients part only says "wheat". Then, how to choose your flour ?!
Actually, in France, it can also get complicated, for instanced when you're looking for "farine de gruau". But to make things complicated, you have to meet a professional cook's recipe or to go get it. In the UK, even in the supermarkets it's complicated. Sometimes there are very few choices, but it's just so unclear! Why?
Because bread flour is sometimes stronger than strong flour, and sometimes stronger than very strong flour. I believe this categorisation is very bad, because unless you actually look at the protein quantity (and sometimes it's not printed), you don't really know how strong your flour is. And you never know how white is white flour (unless you buy it and open the package to see for yourself).
Well, now, my (new and fresh) rules: always buy white flour. Take the strongest one. But if you want to make really good bread, take the least strong one, because the strongest it is, the fastest you make the dough, and the worst flavoured it is. Or take some strong flour but use very cold water and let the dough raise in the fridge... Ok, if you're really in a hurry, you may use very strong flour with warm water, but don't expect to obtain some very good bread.
Yes, I am a Parisian, so I'm know French parisian bread (it's not always good, but it is excellent if you know where to buy it). Well, I do like the taste of English bread, but I just hate the super-insanely-long list of ingredients it contains. So, no, I'm not buying English bread. And yes, I have to bake my own bread (or else I don't eat bread). And no, it's not always good because I'm still experimenting with English flour and my "new" oven.
Ok, when I'm outside and hungry, yes I eat some bread that probably contains an insanely great quantity of ingredients, but then I guess I have to cope with it. It's just not happening when I'm home.
Edit (April, 16th): the very strong flour is very nice to make bread! :-) However, beware, because it raises very quickly!!
If you think my text is confusing, I apology. The subject itself is just so confusing...