>> This is an odd mix of counties, but as they appear in quantity in Leitrim and Fermanagh (Sligo
>> too I think - actually they're all over the place!)

should read:
This is an odd mix of counties, but as they appear in quantity in Leitrim and Fermanagh (Sligo too I think - actually they're all over the place!) the list is incomplete and therefore unrepresentative and shouldn't be used as any basis for a theory.