Hi,
I run a soft furnishing company called Ma Maison and I can certainly help you with your blinds. Blinds will always let the light through on the sides as we have to use a headrail system with a 3.5 cm projection.. This is a legal requirement ( new regulations on cords and hanging systems) so my advice will be to put ablackout curtains in the room. No system will be completely blackout but the curtains will be better.
If you need further info, do not hesitate to contact me.
My website is
www.mamaisondesign.co.uk
with a link at the end
Regards,
Beatrice