This was a bit tricky due to different versions, out-of-date tutorials and the like. Brief notes on a success install are below.

Mid 2016

Trying with Python 3.5

OpenCV 2.4 (wierd, lower version than 2015?) is the stable version but doesn't (?) support Py3

OpenCV 3.1 : py3 support from 3.0 onwards

• Installed using a WHL according to instructions: https://scivision.co/install-opencv-3-0-x-for-python-on-windows/, but probably pip install opencv would work
• Then:

pip install opencv_python-3*win_amd64.whl
pip install numpy

Late 2015

Go it going for Python 2.7

Setup

• Date: 18/8/2015
• Window 10
• LiClipse as a IDE, although this is optional

Failed

• OpenCV 3.0 : Currently supports only Python 2.7
• Offical install guide: Error was that NumPy 1.9 was required (after "import numpy")

Success

• Standard python 2.7
• NumPy 1.9 Pre-built for Windows
• OpenCV 3.0: but will allow use of cv2 (?!)
• Then follow OpenCV install guide, which is simply a copy of cv2.pyd to site-install folder of python
• *** Add C:\opencv\build\x86\vc12\bin (or similiar) to you PATH. This contains the ffmpeg DLL which is required to open videos (VideoCapture)

Optional LiClipse

• After Python 2.7 is installed...
• Make a new project
• Set properties of project, and go to "interpreter".
• "Add new interpreter not listed" and specify python.exe in Python 2.7 directory