In this passage, “the regulators” clearly refers to people within the MHRA, not multiple regulatory agencies.
Here’s why:
The entire paragraph discusses only the MHRA — there’s no mention of the FDA, EMA, or any other authority.
The timeline (“we first submitted the MAA in December 2023”) and the description of ongoing interactions all point to a single agency — the MHRA.
Therefore, when the writer says “the regulators have been very detail oriented”, they’re talking about the MHRA officials or reviewers who are handling that specific application.