Hi Jayne,
There is a webpage about Ambidex reels made by J W Young at the following address: http://www.jwyoungs.co.uk/ambidex.htm
There is also a Medlar Press book coming out "soon" about this Company by Elwyn Attwood. This has been on the cards for ages and a friend of mine has been eagerly awaiting news of the actual date. If anyone knows when it will be out, he would love to know. The webpage still says November 2007, but that is obviously wrong ;o). J W Young made all the reels with "ex" suffixes ie Speedex, Altex, Rapidex etc. and those wonderful purist centrepins (and the John Wilson Heritage centrepin/Ray Walton Rolling pins etc.)
Good luck with your collection. Very well made reels - some of the early ambidex models had half bail-arms which seems very odd today. My friend still needs a mark 5 or 9 (I think?) to complete his collection, so if you get two and want a very good home for one....
Cheers,
Trev