He may not be able to use the country name, but the Irish do have a distinct feature set...maybe falling back on just describing the features as they are instead of referring to a 'shortcut term' would work better, though.
I can't remember where I heard it, but someone told me that instead of comparing your [insert item, character, or activity here] with something that's already around, try describing it as it is.
"You don't advertise your product by comparing it with someone else's. That just makes people think of that other product, which is not what you want."
Heh, seems certain fast food chains are ignoring that piece of advice, if their recent commercials are any indication. But that's way off topic...