I doubt our charity shops are high end, though some, particularly the hospice shop, are particular about what they accept. Must be honest I am quite happy to buy stuff that has originated in Tesco, M&S, Bon Marche, or wherever. I have a nice linen top that had a Edinburgh Woollen Mills label in it. I say had because I always remove labels as they scratch the back of my neck.
Roz
Always look on the bright side, if you can't find it then polish up the dull side.