Lee, find yourself a small (ex-computer) fan that works on 5 or 12 volts DC. Then find a small phone charger (or mains adaptor for a broken toy) that gives a similar (or slightly less) DC output. Stirring the air helps a lot.
Minimise mains electricity connections *inside* the box, and waterproof them.
An upside-down large size thick metal baking dish above the heat source will help to diffuse the heat and avoid hot spots.
Get a digital thermometer with a 'remote' (cheaper if wired) display so that you can read the inside temperature *without* opening the door!
A dimmer switch would allow manual control of the heat input, but gets boring.
An electronic "temperature controller" can be very cheap (see eBay) barely more than a thermometer.
Having a thermometer as well as such a controller would allow you to check the even-ness of the heating (see above about fans and metal trays!)
And a third (immersible) one would allow you to see how much the honey itself had actually warmed up.
In the first instance, you don't want to be heating the honey above about 45C. It will depend on what you have (and how much of it) as to whether you have to hold that temperature for hours or days!
// 35c should be all it takes for fine filtering of show honey //
Certainly, the game is to heat the honey as little as possible ...
the guts and cleaning the fridge out) and Bob's your auntie
