Llloyd, You said your wife has took and passed the IELTS in October, right? I'm assuming that it's the General Training type was the one she took. Now, that IELTS General Training, it has speaking, listening, reading and writing categories. What matters in the spouse visa application are the speaking and listening results only. If she has passed those with a grade of at least 4.0, then she doesn't need to retake the test. And, she doesn't have to take every type of tests that IELTS are providing. Whatever your wife has took in October, as long as the speaking and listening grades is at least 4.0 then that's fine. PLEASE DO NOT CONFUSE YOURSELF.

Ask your wife what IELTS test she took in October. Verify from her what are her test results score in Speaking and Listening. If it's 4.0 and above then she can use that in her spouse visa application. As simple as that.