Michie, too, favours "Spain". This is a joy to read. Were it slipped into an anthology without reference to its origins it would be regarded in some quarters as eyestretchingly racist. To me, it's delicious michief.
This translation nails it. I applaud "Spain" for Celtiberian--the right choice. This is far from my favorite Catullus poem, so making me like it in English is an accomplishment!