I have no idea how prevalent the relevant coins actually were in practice, but in theory in the first decade of the 19th century you could have encountered ¼, ½, 1, 2, 3, 4, 5, 6 and 10 pence, and 1 shilling (12 pence) coins in Ireland. The 5 and 10 pence coins were peculiar denominations issued as bank tokens, while the others were standard British coin of the realm.

I suspect that the reason for issuing the 5 and 10 pence coins was a shortage of regal silver, but in theory the ratio of the 5d to the 6d and the 10d to the shilling matches that of Peter's 2.50 and 3 gulden coins.

Below is the 10 pence from 1805.