It is Stanley Gibbons SG #1282, 17p (low value of the set) Handel's Water Music from 1985, British Composers, European Music Year, a Europa issue stamp set. Issued on the 300th birthday anniversary of Handel.
There is a First Day Cover, a Presentation pack and P.H.Q. cards issued for the set.
Design by W. McLean.
(Taken from Stanley Gibbons Concise 2005 catalog.)