Replace dormer UPVC windows with added shutters?

[sarahemmm]

I desperately need to reduce the heat gain in my two south-facing dormer windows.

 

Ideally I would like to replace the windows with inward-folding bifolds and external shutters. As you can see, there is not space for standard hinged shutters, but I think Bahama shutters, sliding panels or roller shutters could be fitted. The other possibility is to attach a brise soleil.

 

The problem is to find a supplier... so far I have only had snotty responses from places like Shutter Boutique (even though they sell Bahama shutters) and the usual UPVC manufacturers.

 

Has anyone here any suggestions?