This is all interesting stuff. I too have been looking at the same subject recently.
My house has the reflective foil immediately under the tiles which is designed to reflect the heat during the day. There is however no insulation on the floor of the roof/loft space, which does get very hot in teh day and still seems to stay hot well into the evening/night! I have been deliberating on the merits of adding that myself. The developer and others argued that that is less effective because it traps in whatever heat has accumulated during the day, though as mentioned above it would certainly make any AC fitted in the bedrooms more effective/efficient at night. I suspect the developer argued in favour of not installing a blanket of insulation because it saved him money.
We have little ventilation in/from the roof space, only having the slots in the facia board/soffit (?) which of course face the ground so don't encourage much through draught. I like the idea of having extractor fans extracting from the roof space, but am not sure how or where I could position them.
We have sun reflective window blinds and curtain liners inside rooms affected by the later afternoon sun, and they do help, though of course some heat will still be distributed inside the rooms.
It is also important to keep in mind that in LOS walls are only single skin, so quickly and easily transmit heat through to the inside. In this respect, as mentioned above, the positioning of trees and larger shrubs to shade walls and windows is therefore both helpful and important.
I have also looked at having a canopy installed over the larger front patio wall/window, as this is particularly prone to late afternoon sun.
Any other ideas/input are most welcome.
