In Formal letter^x, Regards^x, Whom^x

I am an English businessman. The way you're supposed to sign off a letter depends on how you start. In a letter, if you don't know the name of the person to whom you are sending the letter, you start "Dear Sirs,". If you start with this form, it is correct to end with...

Yours sincerely and Yours faithfully In the UK, traditional valedictions have been mainly replaced by "Yours sincerely" or "Yours faithfully". (Do not paste and copy lengthy material without citing references-- MM) I personally feel that Kind Regards or Best Regards...