Mhairi is the vocative case of Mairi. Native Gaelic speakers wouldn't use Mhairi as a given name, only in its proper grammatical context. But it's been widely adopted by non-Gaelic speakers as a 'different' name, an alternative to Mary I suppose, which everyone was getting bored of :)
Ohh, I see what you mean about MAH-ree being different from 'marry'. Hmm. I can't think of one though...
If Britons were left to tax themselves, there would be no schools, no hospitals ... Just a 500-mile-high statue of Diana, Princess of Wales.