If the bag was held by the pub and the rest of the contents remained (did it contain anything else of value?), I'd seriously suspect the employees of that place. It's hard to prove, of course.

A thief wouldn't take the time to go through your bag at the location; he would simply take it and sort it out in a safe place. There's a small chance that the N810 fell out and someone picked it up seperately from the bag, but that's still far less likely than a curious employee taking a look through the lost-and-found bag.

That city has a big problem with people stealing ****, even people who have plenty of money. I hear lots of Manhattanites avoid tying up their dogs for fear of having them stolen. WTF?