The reason that the inner side of your old tyres were worn more on the inside is due the fact the camber has increased since your 147 is lowered. This can be prevented with slide toe in on the front axle, but you will lose a lot of steer feel. For the right steer feel and handling a front wheel driven car needs toe out (slightly).
When you make use of the correction kit, you're able to get best of both worlds. Great steering feel and no excessive tyre wear.
Like you said, the rear axle can be adjusted also. Standard there is the option to adjust the toe, but it is easier to tweak also the camber on the rear axle.
Please read the whole thread and especially the begin post, I've explained everything there.