Hi,
We used one a few years ago who ws recommended by the Handrail Man @ 01-2981975. If you ring their office and ask for his name and address they should be able to provide. I think they have 2 recommendations but this guy from Rathfarnham (if memory serves me well) is the better one. He did a very nice job.
If you did not get the handrail from them might be best to tell them that it is for something else in case they aren't impressed!