Ireland ½ Penny - George III - No date - 1805?

Hi, this coin matches all specifications of the Irish ½ Penny from 1805, except of the fact there is no date on it.
https://en.numista.com/catalogue/pieces8347.html

Anybody with similar coin or more info please?

Most likely the date has been completely worn off. Even the coin on the Numista page has a date close to being worn off and your coins has significantly more wear.

Here's a coin on ebay where the 18 is still there but the 05 is completely worn away.
https://www.ebay.com/itm/203198386905