I seem to remember that there are two Handel's Gavottes in the John Clare collection and #2 is Sir Syd. See- http://www.ibiblio.org/fiddlers/SIR.htm#SIR_SYDNEY_SMITH'S_MARCH. Seemingly not by Handel at all. Just sounds like him.

Sir Sydney Smith was an admiral in Nelson's navy and had a famous victory at Acre in 1798 so too late for Handel.

The tune has been popular amongst English concertina players since Alistair Anderson used it in his Concertina Workshop.