An update to previous post. While they will be delisted from the Irish and London Exchanges, they will be listed on the Enterprise Securities Market. Don't know how this will affect the ADR's, but there will still be a place for them to be bought and sold.
Might check out the Bank of New York Mellon website to see if they have anything on it. I am going to try and contact them via email. If they continue to market the ADR's, it might be worth getting some at a very low price.