Quick question - cover letter etiquette - should I use person's first name?

[MizZan]

Writing a cover letter. I haven't met the person I'm writing to, but it's an individual who runs the part of the organisation I'm applying to, not just a blanket letter to the HR dept. We would be peers if we met in any other context. In my industry it seems very formal to be addressing someone as 'Mr. Blah' in a letter, but then, this is to accompany a job application, and we haven't met.

What's best practice? Thank you!

[scottishmummy]

I'd address as Ms surname or Mr Surname