At the top of property's official page on Marriott.com, it indicates "Marriott.com / Autograph Collection / London / Hotel." However, it does not show "Autograph Collection" as part of the property's name or logo. This suggests the M by Montcalm still needs to be to aligned with Autograph Collection standards.

The M by Montcalm no longer shows up as part of the Montcalm portfolio at https://www.themontcalm.com/hotels/ . If it's no longer part of Montcalm, I would expect its name to change.

Always good to have another option in London.