Hello Jean and Sue, here are some more ages for John,

1901 at 25 Hope St. Douglas:-
John Henry Cain 39 Gas Worker Douglas
Edith A. Cain 33 Patrick
Lily 11 Douglas
Henry 7 Douglas

his occupation on the 1901 Census = Gas Worker age : 39
his occupation on the 1911 Census = Quarry Labourer age : 45
his occupation on his Marriage in 1917 = General Labourer age : 50
his occupation in 1919 on his son Robert Henry Cain Marriage = Gardener
his occupation on his Death Certificate in 1924 = Gardener age : 59

married 5th june 1917,
john cain [50 ] batchalor-general lab, 18 richmond grove douglas
father robert cain [ carter ]
edith ann cowell [ 49 ] 18 richmond grove spinster charwoman
father john cowell-railway platelayer deceased
witnesses thomas caley and rob kerruish,

Averil