I did my IR prior to my CPL and I felt that it was a good way to go. For a start once you've got your IR out of the way you only have to do 15 hours to get your CPL. Your flying has been sharpened by the IR and you just need to refresh the Nav techniques that you learnt during your PPL.
The only problem I can see with doing your IR in Feb is the possibility of icing which could stop you flying when it's cloudy. Perhaps re-post with a "UK IR in FEB?" question to see if anyone else knows.