you had removed the grilles => try to put them back. The grilles are part of the design loop, and John Atkinson did not removed them to measure the M30.2 Anniversary (which does not emphasize treble). The grilles off -> +1.5dB above 6KHz, IIRC.
Perhaps the XD has been made to sound noticeably more transparent and lit in the treble as this is the current trend with the evolution of Harbeth speakers people have noticed. I have personally experienced this increased clarity and brightness in the treble with the M30 series, starting from the M30 right up to the M30.2 Anniversary.
M30 - rolled off treble and sounds excessively warm and dead (avoid this)
M30.1 - sounds brighter and more open but still warm
M30.2 Anniversary - sounds brighter and more open
M30.2 XD - ?? (no experience with this one)
My experience with the SHL5 and SHL5+ (more than 12 years now) is they sound great with the grilles on, more open and transparent with the grilles removed. Similarly I understand that the grilles are part of the design. Nevertheless, owners have the option to listen with the grilles on or off depending on their listening preference. If one finds the speaker to sound too bright in the treble, leave the grilles on. If a bit more clarity and sparkle are preferred, remove the grilles. I used to listen with the grilles off but now leave them on. It’s quite troublesome to keep removing the grilles and putting them back on every time I want to listen to music.