clandestino
no llevar papel
to add another perspective about B&M - I don't go there v. often but when I have been they've always been friendly to me/us. I still have a soft spot for them from their Lido days though.
When I went, the server just put my change on the counter without a word and then turned to serve someone else. When I had the temerity to ask for a bag for my purchase I was waved rather snootily to a box of bags by the window. It was busy, but nowhere near as busy as the florists, and they couldn't have been nicer.