Take a look at solar control film, purported to cut UV and heat in conservatories. It's not cheap (depending on the size of your conservatory) but its easily applied. I've never used it though
A couple of links for you to look at to give you more info:
http://www.bonwyke.co.uk/retail-wind...protection.php
http://www.windowfilm.co.uk/resident...supertint-poly

