Upgrading to Toucan 1.2.0

I just upgraded Toucan to the latest (non beta) and note that there has been some folder reorganisation which leaves duplicate files (some bitmaps, burp.ex and 7za.exe). Size on disc 3.02M

I installed Toucan to a new folder and it produces a size on disc of 2.60M (after copying my ini files)

Is the installer lacking (I can't find any instructions which say you must install new) or did I do something wrong?