Green’s Dictionary of Slang

down prep.

SE in slang uses

In phrases

down the banks (n.) [the steep banks found in peat bogs; those who fell off them rolled down into the deep, peaty water] [mid-19C+] (US/Irish)

1. a state of failure.

2. a reprimand; thus give it/someone down the banks v., to scold.

down the gurgler (also down the gurgle-hole) [SE gurgler, echoic nickname for plughole]

[1970s+] (Aus.) used of something that has not worked out.

down the pan (also down the chute, ...crapper, ...shitter, up the pan) [i.e. the lavatory pan /crapper n.1 (3)/shitter n.1 (4)]

[1930s+] wasted, lost, ruined; often as go down the pan.