Reclaiming DIRT using Tax Credits

My elderly mother is a DSP pensioner and is making a tax return for the first time (Form 11E). I expect that any PAYE on her pension will be less than her tax credits so there will be no liability. Can she use any of her surplus tax credits to reclaim any of her DIRT or is DIRT a different sort of tax and lost to her?

over 65?

http://www.revenue.ie/en/tax/dirt/dirt-repayments.html

Why is she filing a tax return?

She also has a private pension and received one of those Revenue letters in January. Her tax liability on both the private and state pension plus the DIRT she has paid is less than her tax credits. That's why I'm wondering if she can get her DIRT back?

She can get a DIRT refund if her total income is less than €18,000 (€36,000 for a married couple) and she's over 65.

You cannot use tax credits to reduce DIRT or get a refund of DIRT. Unused tax credits are lost.

Revenue is suggesting to use Form 12s.