Thank you for following up, Christina. Apologies, I only saw your reply just now, and have already completed my stay.

In case it is useful for others in the future: my query was looking for confirmation in advance that a 4pm check out would be possible, when looking to book a room for day use (plat, booking for the previous night, and checking in 8am).

I did not get any replies on addresses from the pre-arrival email or an address provided after an online central customer services query. It would be great for email to work more reliably here.

However, the front desk staff were helpful when I asked on checking out from a prior longer booking, and I got confirmation via a message in the app shortly after checking in for the day-use booking.

The front desk also sorted out a room move after I found that the room booked for the longer stay did not match the description. The Marriott web site described the corner suite rooms as having a “desk and ergonomic chair”, but there was no desk at all (from memory 604)