Indefinite Leave to Remain SET(M)

Hi all,

I am in the process of applying for Indefinite Leave to Remain as a spouse of a British citizen, but we just realised that my partner's passport expired on 3d of August 2021. I need to submit my application before the 23rd of August 2021 as that is when my current residence permit (on the 5 year route) expires. There are no available appointments for him to renew his passport fast track for the next 2 weeks.
Do you know whether my partner's expired passport can be used to proof his identity in my application?

Thank you in advance.

Hi,
Thank you for your answer.
I have another question. I have just completed the online application and the only option I am getting in the end is Standard Service.
Do you happen to know whether priority service is available for SET(M) applications? I am confused as a quick google search shows gov.uk websites saying priority and super priority service (£500 and £800) is available foe SET(M), and on the other hand, I am not given the option to choose a priority service.