The most famous early teen girl comic that put the photo-story on the map. Highly collectible and becoming more available thanks to eBay UK and other auction sites. Free gift with #1 Twin Heart Ring is rare and would add £60-£75 to the value. 1st Jackie & Diana was 4th Dec 1976 (issue number 674 with thanks Michael Lawrence for the info).
The first Jackie Summer Special was in 1976 and there was a Spring Special 1979. The annuals ran from 1966 up to 1993.
Note: some PR issues may have no value. Selected issues in FN, VF or VF/NM may not exist in some titles.