The Answer: In the toaster!
How it migrated there is a matter of conjecture, probably involving the effects of gravity from the top of the coffee maker and relatively between objects (ie it has to fall at 45 degrees), but Friday morning my other half decided to have toast. Now the toaster is a novelty job that puts a smiley on the bread. Nothing odd was noticed except for a key shaped mark at one corner and general lack of cooking on one slice. I therefore come home to "the toaster needs fixing". There, in one slot was the Triumph key with nothing worse than a wire mark either side of the plastic part and a charity key fob that's now just a green blob! For a woman who can smell oil on my boots as I come into cloth throwing range you'd have thought burning key fob might have given the game away, but it seems the stuff is odourless and doesn't even alter the taste of toast made with week old supermarket bread.
Andy