Unit marked P14 (1913) Bayonet.

[Surpmil]

After the Royal Garrison Artillery left in 1906, Canada manned the forts with the newly-constituted Canadian Garrison Artillery.

Straight from Wiki:

The Royal Garrison Artillery came into existence as a separate entity when existing coastal defence, mountain, siege and heavy batteries of the Royal Artillery were amalgamated into a new sub-branch. A royal warrant provided that from 1 June 1899:

"... the mounted and dismounted branches of the Royal Regiment of Artillery shall be separated into two corps... to be named respectively (a) the Royal Horse Artillery and the Royal Field Artillery: (b) the Royal Garrison Artillery."[2]

The RHA were originally created to accompany the cavalry I believe: lighter guns and limbers and therefore faster.

There were forts and batteries all over the Empire coasts that needed artillerymen, particularly where there where RN bases, as there was in Esquimalt: the base of the Pacific Squadron until 1905.