i ordered 5x3ft and 4x2ft of 3mm polycarbonate sheet from these guys on friday and it turned up today , so extremely good service imo and a good price at ?105 to my door. there on ebay but i found it easier to call them
http://cgi.ebay.co.uk/ws/eBayISAPI.d...e=STRK:MEWA:IT
highly recommended
by the way 5x3ft and 4x2ft is what you need for a rear window, both quarters and one piece front windows on a saloon