There was a fairly sizeable workshop area out the back and their website says that "Cyclopaedia is run by Cyclists for Cyclists - every member of staff is a Cyclist, some are triathletes as well!" which I can believe and I think we'll all agree that this is essential when looking for any kind of specialist shop. They deal with over 50 different suppliers and stock 200 brands so they should have what you need, if they don't they will try and order it for you.
I haven't been to any other bike shops in Cardiff yet but I'll happily recommend this one for now cause it was well stocked and had the kind of feeling you get when you go to a skater owned skate shop or an independent record store, know what I mean?
116 Crwys Road
When you pop in there tell them that Fixed Gear Wales sent you, happy riding! :-)