Green’s Dictionary of Slang

1. a shower (of rain).

1998		R. Puxley Fresh Rabbit.
2003		B. Dark Dirty Cockney Rhy. Sl. 44: Typical! No rain for weeks and then a David Gower just when I want to mow the lawn.

2. (N.Z. prison) a shower (for washing).

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 52/2: David Gower n. shower.