I write no more than either, "Apologies for the delayed response," or "Apologies...

alsetmusic 5 months ago | parent | context | favorite | on: Do not apologize for replying late to my email

I write no more than either, "Apologies for the delayed response," or "Apologies for the delayed response, I've been out of the office unexpectedly." Very business-like. Tone neutral. Easy to digest and move on.