@sophocles,
It depends what you mean by a Joey. Before 1855 it was a slang term for a groat, which was worth four old pence. However, just before decimalisation it was the term some used for a three penny piece.
Old money was pounds, shillings and pence, LSD. There used to be twelve old pennies to a shilling. There were twenty shillings to a pound. That meant that come decimalisation a shilling was worth five new pence.
A Bob is an old term for a shilling, a tanner six old pence.
In old money it would be one shilling plus six pence plus three or for pence.
So, one shilling and nine or ten pence which would probably work out at nine new pence today.