GMM wrote:
We defrost quite a few freezers at work and the simple way to melt the
ice quickly is to direct and regular desk-type fan on it. This will
minimise the amount of time the contents are out of the freezer by a
significant amount. Frozen food in something well insulated should
keep cold for a good few hours.

A fan heater might be even better, though I've never tried it.

I've used a fan heater on several occasions, however, I'd caution with a
frost-free that there's a hell of a lot of plastic shrouding etc,
betweeen the freezer cavity and the "innards". I *thought* I'd defrosted
a frost-free when I had problems with over-temp, but it was only by
removing the shroud (4 screws, against the bar wall of the freezer
compartment, easy pull-out) that revealed the polar ice-cap loitering
behind. THEN, the fan heater worked effectively. Usual rules of water
and electricity not mixing apply.