Just thought i'd give a quick mention to him as i've used him for a few bits and seems to really know his stuff. He's got what looks like a tiny corner shop but he has stacks of spares and specialises in hard to find bits, particularly for older Hondas. He's not the cheapest but might have a part you've looked long and hard for or at least can source it and does mail order too...
http://www.johnoldfield.co.uk/