Half inch = to pinch (to steal)
Hammer and tack = ya' back
Hammer and tack = a zac (sixpence)
Hanky panky = cranky (bad tempered)
Hansom cab = a scab (a non-unionist)
Happy hour = a shower
Harold Holt = salt
Harold Holt = a bolt (shoot through)
Hi-diddle-diddle = a piddle (to urinate)
Hi-diddle-diddle = the middle
Hit and miss = to piss (urinate)
Highland fling = string
Holy Ghost = the post (mail/letters)
Holy Ghost = toast
Holy Ghosts = fence posts
Holla log = dog
Home on the range = change (money)
Honky tonk = plonk (cheap wine)
Horse and cart = the start
Horse and cart = to fart
Horse and foal = the dole
Horses hoff = a poof (homosexual)
Hot cross bun = the sun
Hot potater = later (pronounced that way)