Dear Sir 'stroke' Madam,
I'm writing to inform you of a fire which has broken out at the premises of...
(No. That's too formal.)
Dear Sir 'stroke' Madam,
Fire 'exclamation mark', Fire 'exclamation mark', Help me 'exclamation mark'.
123, Carendon road. Looking forward to hearing from you.
All the best, Maurice Moss