Thanks for all the help guys!
Just to clear up a few points, we do use a prefix for VC, as a rule VC will pick up my wifes voice and what she is saying, just the confidence isn't high enough to trigger the command, although it's not uncommon for VC.Not Recognized to pop up once or twice whilst she is trying to give any command too!
I have tried fiddling with my mic input levels (I have one stand alone Blue Yeti Pro, with input set to around 10/100, with all 4 of the built in mic's active, it is placed about 6 inches behind myself and my wifes head, where it is attached to the back of our couch....
Prefix confidence is set to 60 and Command confidence level set to 50, although lowering these settings does seem to end up giving my wife better results, VC tends to pick up a lot of false positives from myself and my wife ( random commands even in prefix mode but)
Her accent isn't really all that bad, pretty standard BC Canadian accent with a touch of Scottish twang in there, If anything, I would think my voice (Broad British Yorkshire accent) would be harder for VC to understand!
Pretty frustrating because I want VC to work as amazingly with her as it does with me!
I plan on getting a Kinect to try out with VC next month, maybe even using VAC to use the existing mic I have and the Kinect at the same time( providing results are all good)
Will keep you all updated and currently tinkering with having 2 instances of VC running too.
Thanks guys