Child Modelling agencies..?

Hello, I have registered my son on a modelling agency. My eldest daughter was on 2 agencies and never got any work so I'm wary about shelling out again but I know that money can be made from modelling to put to my sons future. I always believed that if an agency wants you that you should not have to pay anything out but all the ones I have come across expect a portfolio and registration fees (which I understand are a need) We have spoken to the agency who ure us that he is what they want as he is photogenic on his attached pics, that he has blonde curly hair and blue eyes which is a rarity but I always think they would say that. They said they wouldn't take him on if they didn't think he could get work. They are a reputable company and have child actors for UK TV programs such as Coronation Street..I just know what to do.