1923 was the year Stan's father joined Trinity House ... the Lighthouse Service for England and Wales.

He had to attend the training depot in Blackwell in London first, before he could serve on any lighthouses. Not sure how long he had to train there. Blackwell had a lighthouse built on the bank of the river Thames. This was used for all kinds of experiments as well as the training of the new lighthouse keepers.
http://www.lighthouse-duo.net/Ball/FLK.htm