Golden retriever found Clontarf area

I was in Clontarf this evening at about 6PM when a golden retriever darted out in front of my car. I stopped to see if I could see an owner about, but there was nobody with the dog. He then ran back across the road which really worried me as it was obvious he wasn’t road weary.

When I eventually got hold of him, I found a phone number on his collar, but up to now nobody is answering, and I’ve left a load of messages. He is currently in my wife’s mothers back garden in Clontarf, but she can only hold him until tomorrow as her own dog and cat are going crazy. Anybody have any ideas what I should do next? I’ve already checked with a few people, but none are in a position to give him a temporary home.