I'm not a Welsh honey judge but have heard Robert Brewer (one of the main Welsh honey judge teachers in the US) give several talks on the subject. Honey is judged on the presentation because honey judging is supposed to model how we should handle our honey when we sell it or give it to others. It isn't really fair to judge honey on the taste since the bees are in charge of that.
So as I understand it, if there are two entries of honey of equal presentation, then the taste of the honey determines the blue ribbon. Otherwise it's about no fingerprints inside or outside of the jar, no honey on the jar lid, fill to the proper level, no bubbles at the top of the honey, clear well-filtered honey with a good aroma - (no chemical smell from cleaners - your jar should be washed well, but don't use Windex, for example), etc.
The way it is about the quality of the honey is that the clearer the honey, the better because that represents how you filtered the honey. If there's debris floating in a honey jar, even if it's wax, unless we're talking about chunk honey, that's a no-no.
I've given lots of talks on how to prepare honey for a honey show and here's a slide show I use:http://beekeeperlinda.blogspot.com/2011/06/preparing-honey-and-wax-for-competition.html
Also our club's web site has really clear and specific rules for honey shows that we developed with Robert Brewer's help:http://www.metroatlantabeekeepers.org/honey_contest_rules.htm
Linda T in Atlanta