MA has the right of it with the whole Catholic names thing. I live in on the west coast of Scotland, not to far from Glasgow actually, and there are a lot of names that you just couldn't call your child. It's not very sensible, here, to give any indication that you might be RC, so you wouldn't find any Padraics/Patricks, Declans, Lachlanns, Francis, Dominics or anything else here at all, same with girls names that might be seen as Catholic (Clemency, Theresa, Rosemarie or whatever). It can lead to a great deal of unpleasantness for a child, or even an adult.
Names are very loaded, here, and you won't find kids with names which might indicate "class" (for want of a better word) either, so no Marcus, Casper, Hugo, Struan, Hector or Alisdair either.
Sweetkitty had a thread recently about this very thing, as she was struggling to find a name for her expected baby boy that was safe.