Hello RB73,
I had never heard of any English fragrances before joining B&B. I mean other than Yardley, English Leather and British Sterling which are all sold in drug stores here. So I recently ordered sample sets from Penhaligon's and Floris. Some have described them as "old man" scents, but I am 53 so ...
I also got a bottle of Creed Royal Scottish Lavender and one of Atkinsons English Lavender (I was on a lavender kick).
To answer your question though, I don't it is difficult to get any of the high line scents here if you live in a large metropolitan area like New York, Chicago, Miami or Los Angeles. There is a Penhaligon's store downtown and the better department stores here will also stock some of the high end stuff. The biggest fear would be counterfeits from China being sold by street vendors.
I still get much of what I want from online vendors. Shop London is where I got my Penhaligon's and Floris soaps and scents. They are located in Charlottesville, VA. I also don't mind ordering from the U.K. as I got my razors and brushes from The English Shaving Company.
By the way, I really like the scents from both Penhaligon's and Floris. The sample sets include men's, women's and unisex samples. Beyond that, Shop London includes free samples with every order so I have a few extras from Floris. Oddly, my favorite scent is one of the women's perfume samples, Floris Lily of the Valley. I put a dab in my mustache and just breathe normally. Indugence!