i think the requirements are life in uk test (if your wifes english is above ESOL Entry 3 level)

OR

an approved ESOL qualification through taking a course
which includes citizenship materials “Skills for Life” qualification in speaking and listening at Entry Level (if your wifes english is below ESOL Entry 3 level)

two ESOL Units at Access Level under the Scottish Credit
and Qualifications Framework approved by the Scottish
Qualifications Authority.
(if you live in Scotland)

If you have not reached ESOL Entry Level 3 standard, the evidence of your ESOL qualification will need to include a letter from the
college confirming that you have progressed by at least one level from the level at which you started, and that the course included
citizenship materials.

the ESOL courses are 1 year, so your asawa doesn't have time to take a course.

hope im correct

regards
martin