Well it took a while but I finally got my reply from the CAA today. The good news is I can use my class 1 (Gained end of Oct 03) for class 2 privileges for up to 5 years (for the under 30's) from the date of issue ie until Oct 08. You DO NOT need to retake the class 1 initial IF you revalidate before the end of the 5 years of class 2 validity.
Thanks for all the replies
NT