Yes you can just gently warm candied honey to get it to return to liquid.
As for creaming: I guess that may work if you mix it for ages. basically that IS how you make creamed honey- only for a very good creamed honey you start with a ‘seed’ of very very fine crystals- not regular crystallized honey which has larger crystals. I suppose if you mix it thoroughly enough and for long enough you will break down the original crystals… but if even a few survive then the entire batch might end up being more like candied honey than creamed.
Basically the way it works is a single crystal sets off a chain reaction - and the crystals that form around it are the same size as the original ‘seed’ crystal.
So the best approach is to either use good creamed honey as your seed and mix it in well at a ratio of roughly 1 part seed to 10 parts honey- or - get some candied honey and use a mortar and pestle to break the crystals down until they are so small you can’t really register them as individual crystals on your tongue. This can take quite a long time… The finer they are the better the creamed honey will be.
Once you have made a good seed once- you don’t have to do it again as you just keep some of your creamed honey to act as your seed for the next batch.
@Rodderick I just noticed above you said you put them in a fridge for several weeks: I can confirm that my mum simply stores them in a cool room when the temps are around 14C and they set in under a week. The only problem with that is it can’t be done in summer. We are considering getting an old fridge and seeing if there is a way to get it to run at 14c.