Actually the best thing I have defrosted this freezer with was the mobile air con unit. Physics baby!
I parked it in front of the freezer with the exhaust pointed into the freezer. Defrosted it, removing all ice, in about an hour. Added bonus of dehumidifying the room and warming it up generally.
But it's upstairs and it weighs a ton (or about 15Kg). Now I wish I'd gone up and got it as half way though a bottle of wine and I can still hear ice falling
I have to reload the freezer tonight, no matter how tired or drunk I am.