Rob try this link. It's from ebay, he has dismantled 2 Rs Turbo Mark 4's. He hasn't listed the sunroof as available but he does mention a shell maybe the sunroof is on the shell. Best of Luck, I know how you feel, nothing worse when you are looking a for a part. You don't know anybody who has a 87 spec drivers door card.

http://cgi.ebay.ie/FORD-ESCORT-RS-TU...QQcmdZViewItem