In theory if revenue deduct the prsi on foot of a form 11 there is nothing stopping someone from applying for a rebate from social welfare if under the €5K limit.
This might be coming a bit late but may serve you for the next time. Its dead easy to get a letter of residence from Revenue directly or download it if you are registered for 'My Account' on the Revenue website. Hope this helps.
It is if the WHT is more than the 15% (max) you can offset against the 33% Irish DIRT and you want to reclaim it. Hope you have the language skills to communicate with the country you'll be claiming it from! Best to stick with the investments that don't deduct WHT as you'll only have the Irish DIRT to contend with.