Some more beaten up coins to look at here!
1784 2 Reales, Colonial Spain, Lima m/m (Carolus III)
1784 MI 2 Reales of Peru rev 
1784 MI 2 Reales of Peru obv
Part of the group of ‘fractionals’ based on a ‘Piece of Eight’ – which they made the most of … fairly sure they made a 1 as well as a 1/2 but nowhere near the quantity of the 8s….{‘MI’ are the initials of the assayer and follow the value}.
I think the Lima mintmark is one of the uncommon ones but there are a few – Mexico, Potosi in Chile…lots as well as Madrid.
1796 20 Grana, Kingdom of Sicily (Ferdinand IV)
1796 20 Grana of The Kingdom of Sicily rev 
1796 20 Grana of The Kingdom of Sicily obv
(I have no idea what other ones they made, they might not even have had a big one, say maybe 80 Granas…?)
’96 was the year they declared war on the revolutionary French, in the process becoming allied to Great Britain.
The English shilling of 1787 is very similar to these and that coin certainly circulated in Australia.
Happy Collecting!
pre1946silver.com 