By: F. L. Korean
The 1997-SG, Part 18, lists and assigns stamp numbers in chronological order for commemorative stamps; however, it periodically lists "definitive stamps" and any respective "Coil stamps", by a group of stamp numbers, inserted about every five-years of issue.
Souviner Sheets, which Stanely Gibbons calls "Miniature Sheets" are assigned an "MS----" number, using the next sequential number available.
The last stamp number assigned in the 1997 SG Catalogue is MS2211 for the four S/S of the Mushroom (4th Series) Issues; Aug. 19, 1996.
I have looked at Stanley Gibbons' Web-Site "My collection", beginning with Literature Series (2nd Issue);
Sept. 16, 1996, and continuing thru the first issue of 2005.
Stanley Gibbon's stamps Web-Site