I hate to follow up to a posting, but here is more information from the
same thread on the comp.sys.hp.hpux group:
 
The correct one according to HP
 
 
# Greenwich Mean Time, British Summer Time
GMT0BST
0 3 25-31 3  1983-1984 0   BST-1
0 3 23-29 3  1985-1990 0   BST-1
0 3 25-31 3  1991-1994 0   BST-1
0 2 25-31 3  1995-2038 0   BST-1
0 1 25-31 10 1983-1985 0   GMT0
0 1 23-29 10 1986-1994 0   GMT0
0 1 21-27 10 1995      0   GMT0
0 1 25-31 10 1996-2038 0   GMT0