The phrase "delay in my reply" is correct and can be used in written English.
You can use it when you want to apologize for taking a long time to respond. For example, "I apologize for the delay in my reply - I was very busy this week."
In my reply to his post, I said that all roads lead to the Science desk.
In my reply I present a re-analysis of the data of the Smithsonian Astrophysical Observatory (SAO).
Apologies for the delay in my updates.
End-to-end latency: the delay in successfully replied service discovery phases between the UA and the SAs.
Main challenged the prime minister over the three-month delay in replying to her letter in the House of Commons on Wednesday.
In its adjudication, the commission criticised the papers for the six-week delay in replying and for standing by their story.
"But on the whole I fancy that the Hun gets more back than he gives, but that never seems any consolation when they are dropping anywhere near one!!" The soldier continues in the 1917 letter to apologise for his "delay" in replying to a message from the school, and says he and a friend always look out for Rossall's sports results.
Moore, delaying in his reply in order to buy time, eventually declined that demand, essentially calling MacDonald's bluff.
For the assessment battery shown below (Usui et al. 2003), responses were rated as errors when subjects made either no response (arrest), delay in response (slowing), or an incorrect verbal reply (error) during stimulation (Table 2).
Lack of referral reply, delay in receiving the consultant's reply letter, and insufficient detail in reply letters are common concerns expressed by surgeons elsewhere [ 51].
