Are you buying the shutters online? Or from a store? If online don't they have a contact address to email for further instructions? If from a store, don't they do installation?

Bay Windows can be gorgeous but need more space away from outside footpaths and driveways to look best and the new framework would have to be about 75cms out from the existing outside walls to include a comfortable window seat..and installing a new bay window in an existing window may not be cheaper because you have to first remove the old window and then custom build a new structure and window to suit the available space so it may be better to consider another position around the house, even if it means removing a solid wall..look for a wall space at least 2m wide with at least 1m plus a footpath width clear space outside, preferably looking onto the back garden not the neighbour's side fence

we need some photos or a plan showing the dimensions of the spaces and the width and height of each window and what are the walls made out of but do you want or need to be able to go through the doors to an outside patio or is it just that you want more ventilation?

Many thanks for your comments folks. I was wondering if there was something out there I didn't know about... cellular blinds I haven't tried but I know they are expensive. Blockout curtains I know work well with pelmets and when extended past the windows at the side, and that doesn't work out cheaply either. I imagine we will need a combination of these. We will probably put a pergola out to the east side of the house with a deciduous vine, so not worried too much about summer. Will use canvas external blinds if it makes the house too hot. I like sun in the morning to get me going, and avoid it in the afternoon and on summer evenings.