"Mòran taing, a Mhàiri."
Translation:Many thanks, Mairi.
Tricky one! "Many thanks" is a literal translation, but I wouldn't use it very much - if at all - in English. But "thanks a lot" is often used sarcastically to mean the opposite. You would have to hear the tone it was said in to know. I would probably say "thank you very much" if I really meant it.