I know that the latest raft of the bonds being offered make mention to the fact that Bank of Ireland are treated as the deposit taker and are covered by the depositor protection scheme up to €100,000 and the government guarantee scheme up to 2010.
usually these bonds are deposit based so the funds never leave the deposit takers books. most often the bond offeror will take an advance payment on the interest accruing over the term of the bond and will use those funds to purchase options, or some other kind of derivative, they will make their money by reducing the participation rate offered to the investor.
The underlying guarantee on the investment will be provided by the institution who arranges the derivatives involved and BCP may use a number of different institutions over time. These institutions may or may not have a guarantee scheme in place so it may be worth checking out. For the latest offering it is Bank of Ireland, but it may have been a different institution in the past.