How much Mortgage interest Tax Relief would I be entitled to?

I'm new to this site and have already learned so much.
My mom loaned me the money for a house I bought four years ago, which I have been paying her back interest free for the last four years. I now want to buy a property, (which I intend to rent) in Bulgaria for €75k so I will need a mortgage. I intend to release equity from my house in Ireland, and pay the Bulgarian property in cash. I may also take out more, and give my mom back a lump sum. I have gotten married this year and want to know if I would be entitled to the married first time buyers' mortgage tax relief which I think works out at €1600 credit each year?
All advice is appreciated!

The purpose of the loan is not for principal residence, therefore you cannot claim mortgage interest relief. If the property is in Ireland, the interest would be deductible against the rent. You need to be clear on the tax treatment of the Bulgarian property. If you return the income (Case IV?) then deductions like interest would be allowed. Foreign properties and their tax treatment needs careful consideration as regards local and Irish tax. As usual, the Revenue have little guidance on this.

You also need to make sure there is a double taxation agreement between Ireland & Bulgaria and that it specificially covers investment income, otherwise you will be liable to pay tax in both countries and connot offset the bulgarian tax against the irish tax.