Thank you. Done, and I do appreciate your asssistance.

That said, this really is the kind of simple thing that should have just worked properly -- or, failing that, been quick and easy for customer care to sort out at the first, second or third time of asking.

Is there anyone here who does not doubt my sanity for chasing an SNU in the first place?

Dear IMH,
Thank you for your message.
We will raise the topic again with the teams we notified.

Thanks again for your patience,

With my best regards,
Amy

The missing SNU was posted minutes after AccorHotels Concierge received my message. :)

Many thanks for that, Amy.

The list of exclusions has been again updated on 12/02.
https://all.accor.com/loyalty-progra...pdf-snu.en.pdf

Compared to the 29/01version,
have been removed from the exclusion list :
- Mövenpick Yanbu (Saudi Arabia)
- Mövenpick BDMS Wellness Resort Bangkok (Thailand)
- Pullman Liverpool (UK)

have been added to the exclusion list :
- SLS Baha Mar (Bahamas)
- SLS Beverly Hills (USA)
- SLS Brickell (USA)
- SLS LUX Brickell (USA)
- Mövenpick Resort Waverly Phu Quoc (Vietnam)

I just read this thread. I also wanted to use my SNU's for an existing booking. First contacted customer service by email, got a general marketing reply about SNU without any indication how to use them. Then I contacted the hotel (Fairmont Empress, Victoria). Got reply that I should contact central reservations by email. The email provided bounced, but in the bounced back message the new email address was mentioned. That worked, sent the email request a week ago, now waiting for reply. But probably with the answer I read in the thread: cancel and re-book. Very cumbersome and time consuming.

Have attempted to redeem my SNU twice now, one an M Gallery property and one a Sofitel property.
The M Gallery (Melbourne) property said that I could not use the SNU as i had booked a flexible rate and to use it, i would need to change to a non-flexible rate!
The Sofitel (Wellington) property said that I could not use the SNU as I had booked a non-flexible rate and to be able to use it, i would need to change to a flexible rate!

Reading this thread, i dont ever think ill be able to redeem my SNU's

edit: after more than 2 weeks still no response from customer service

As I am far from certain that I will ever use ANY of my SNUs, and am certainly in no hurry to try to do so, I went through "normal" (?) channels to claim my missing one (arising from Accor's belated crediting of my December 2019 stay). I emailed Customer Care on January 12, received a response from them on January 29 telling me my request had been forwarded to the technical team, and on February 25 had a response from them advising me that the missing SNU had been credited--which, upon checking, I confirmed was indeed the case!

You cant apply a SNU to a Accor Plus redemption....3/3 failures in attempting to use the SNU.

To be fair, that is stated explicitly as ineligible in the T and Cs.. most of the issues experienced have been around trying to get SNUs applied even when eligible under the T and Cs.

Could you link me to the T&C's? Would be interested in reading them to find out how I can possible use them.
Thanks

Sure, it's section 9.3 here https://all.accor.com/loyalty-progra...ditions-en.pdf

Does anybody know if SNU's can be applied upon arrival during checking in?

You cannot. The membership T and Cs (front page of all.accor.com footer) say

Members who wish to use one or several Suite Night Upgrade(s) during their stay must pre-
book prior to the stay.

and you need to book contacting the hotel or the call center. You cannot do it yet on website/apps.