Thanks everyone for your kind comments about the missing swift. I called again today to the missing items office at Stansted. They haven’t seen it. I left it in a W.H. Smith in the main terminal. The guy at found items said “Well, I have a whole stack of credit cards sent here from W.H. Smith, but no box like yours.” After so many days I don’t think it’s going to show up. It’s probably for sale on eBay right now.
I have tracked down a web shop in NL where I can buy one, for the same price I just paid in London. The shop itself is in the farthest southern corner of this country, but you can order online! It’s called Venne. I might have to go visit them one day.