A couple of updates on the hotel - one personal and positive, the other a new minor irritation.
Normally, Marriotts seem to allocate room time the night before arrival so checking a reservation on the day of arrival will give a good indication of whether an upgrade has been processed. However for my last and next stays at CH, I can see I've been allocated an Executive Suite several days ahead of arrival (Thursday for a Sunday arrival in this case). As a PP< I find recognition here superb with something like an 80% hit rate for suite upgrades.
The minor annoyance is that the landlord has clearly had some discussions with the hotel and has "banned" guests from using the rear entrance to the hotel. This seems to involve locking the doors to the lift lobby and putting signs up at the top and bottom of the stairs saying "No access for Marriott guests". I ignored them when there last week and wasn't challenged, but it is something the hotel needs to work through with the building landlord for those of us who need to get to and from the rear of the hotel.
P.S. I'll check the latest lounge status update on Sunday when I'm next there.