Extenuating circumstances evidence; would therapy discharge letter be accepted?

Hi all,

As the title says.

I have a deadline due next week but I am applying for extenuating circumstances (mental heath) - I do not have a letter from my doctor but have been having weekly therapy sessions for the last four months which only finished last week. They sent me a letter this week confirming my attendance on all these dates alongside my PHQ-9/GAD-7 scores which was signed and dated by my therapist.

Would this be suitable or do I need to try and get something from the doctor?

Thanks.