Hi
Congratulations for your ILR.
If you read the website:
https://www.gov.uk/english-language
You can prove it by having either:
-an English qualification at B1 level
-a degree taught or researched in English
Degrees taught or researched in English
You’ll need to prove your degree was both:
taught or researched in English
confirmed by UK NARIC as the equivalent of a bachelor’s, master’s or PhD degree in the UK
You’ll need your original degree certificate and one of the following:
a printout from the points-based calculator with the equivalent level of your degree and the level of English
an original letter or certificate from UK NARIC confirming the equivalent level of your degree, plus an official letter from your university with your name and degree confirming that your degree was taught in English
an original and official certificate from your university confirming the degree was taught or researched in a majority English-speaking country (except Canada)
If you see my thread where you just commented that NARIC English Language Assessment will give you certificate for (CEFR level C1) level, where as B1 level is required to proof English.
By the way, why your spouse is not taking English (CEFR level B1) test?? It is only 10, 15 min test (speaking and Listening) and can be done in few days.