I was at Leicester-based convention Amecon, and as I don't believe any convention officials are members of the site I thought I'd announce here the result and my pick of the entries (NOTE: other videos listed are opinion only!). The winner of the AMV competition was The Narutrix, by Inertia.
Other videos I liked:
toothycat.net's Move On, one of very, very few Yokohama Kaidashi Kikou videos and a fairly calmly enjoyable video throughout.
Jane's Last Dream- not uploaded on the Org as far as I can tell, but this video was the most incredible I-want-to-see-that-series video I've seen. Sadly, I have no more information than the title- noone in the room knew what the series was.
Lem T Lemming's 'World of the Undead' was good, also not uploaded.
A mention should go to i luv cats's Hellsing video- likewise not uploaded, and even the title was unclear at the showing.
Sorry for there being so many unavailable videos- that's all I can find from the worthy con entrants.