Dogs being accepted on buses

I am a motorhomer and when I was at the Brecon site, some time ago I and decided to catch the bus to Brecon from the site with my 2 dogs.  I was in the queue when a couple arrived who had 3 small dogs.  When the bus arrived, the driver refused to allow us on the bus as we had dogs with us. I am not sure if this was because the driver did not allow dogs full stop, did not want so many dogs on the bus or if is the policy of that particular bus company.  I have never been refused passage or in fact had any hassle from a bus company driver due to having the dogs with me (although I was once refused passage by a replacement train, coach driver) and wondered if anyone has had this problem before in Brecon or anywhere else in the UK?