Good question. I asked about this several years ago when I took out a mortgage in London. I beleive that it is exactly the same situation here in Ireland. It would have cost an additional £1,000, but in the end I did not need one because I had a favourable LTV.
According to my insurance broker, there was absolutely no benefit for the buyer of a property in having a mortgage indemnity bond. He explained that the house purchaser effectively pays for an insurance policy for the lender. If the purchaser defaults on the loan then the insurance company who sold the mortgage indemnity bond compensates the mortgage lender, the debt would transfer to the insurance company, who would then pursure the loan defaulter for the balance of the debt.
SM