Green’s Dictionary of Slang

didgy adj.

[? var. on SE colloq. dodgy]

crazy, insane.

[UK]J.J. Connolly Layer Cake 289: When this old bill comes out again he’s like lost it, gone all fuckin didgy.
[UK]J.J. Connolly Viva La Madness 20: A completely paranoid nut-nut who could get didgy if an unfamiliar milkman delivered his milk.