Roof Tile for Low Pitch Roof

I'm planning a sun room for the back of my house. The pitch of the new roof will be around 15 degrees. This is governed by the angle to avoid some upstairs windows and cills.

I've looked up the Tegral and Capco sites and the Tegral 'Melbourn' is the only tile that is guaranteed for this angle. Unfortunately, it only comes in one colour (grey) and this does not match the colour of the existing house (terra cotta).

I have other options such as a composite 'tile look alike', plus metal such as copper etc.

Does anyone know of another tile that will work at this angle. Or are there any other options (maybe use an 'ordinary' tile but do something else to make it water proof at the low angle).

Any feedback would be greatly appreciated.