Good morning there Yours sincerely and Yours faithfully are both British. If you don’t know the recipient, then you should use Yours faithfully. On the other hand, if you do know the recipient, the correct closure is yours sincerely. The American tend to use Yours truly instead of yours faithfully ( correct me if I am wrong dear American native speakers *-*) Instead of Yours sincereley, the Americans usually reverse it and say Sincerely yours. The question: „ Mr or Mr“ is easier to answer. Mr is standard British English, Mr. is standard American English.