The Ben Sherman shirts we wore tended to be plain or stripped but the Brutus shirts were tartan or check. For the sussed boys who wore American import short-sleeved shirts the check was a popular choice.
I wore Fred Perrys all through the 60's. I have holiday photos of my dad, his mate, me aged about 11 and my brother aged nine all wearing FPs in about 1964. If you bought a Tennis shirt that is what you got. There wasn't a wide range of brands available. Original skinheads did wear them in our area. John Smedleys with the larger collar were worn by my older Mod cousins.
To be a paper millionaire in West London near Stamford Bridge you only need to have your own house in that area. I have worked with a few chaps in that situation who bought their houses in the 70's and are now sitting pretty.