No, he was born 1885, quite young to be mayor in 1918, but there you go.
SHJ was a corn merchant and other things.  The business, even in 1933 was in his father's name, M Jackson & son, despite
Deaths Jun 1908 
JACKSON    Matthew    (55)    Louth    7a   328
Syd also died young
Deaths Jun 1932 
JACKSON    Sydney H    (47)    Louth    7a   619