Thanks for your replies. We moved the cider yesterday. I suspect it may have already had excessive oxygen contact, having tried some from near the lees - I haven't tried cooking sherry, but I would expect it to taste a little like this. Still, we'll keep it and see what happens, since these are from our apples. We put a blob of honey in each and the airlock is bubbling a little today, so at least some kind of fermentation is still happening. Our other batch, a later experiment with store-bought juice and skimmed yeast, was vinegary and went down the sink. :P
Still, now we have some decent equipment, steriliser and a new packet of yeast we will start again soon, properly, and should see some improvement.
We had a big juicer on loan from a friend and I was going to experiment with different types of apple, but she needed it back and so our next experimentation will be with basic store-bought juice and trying to get a tasty baseline, possibly seeing what kind of difference more or less honey will make to it.