Thanks Dave.
I restarted the freezer yesterday and left it running overnight. There wasn’t any condensation on the outside, and nowhere felt colder than the metal skin of the washing machine. It sounded normal and the food compartment inside seemed as cold as usual. There wasn’t any more dripping when I turned it off again (although I realise overnight doesn’t allow much time for ice build up even with this humidity). Do you have any other suggestions? Can you have the insulation problem without cold spots? I’m having trouble seeing how water could get to where it was coming out unless there was either an ice buildup outside the food compartment or something leaking in the machinery.