I don't have any personal experience - you could contact your local papers, speak to their photographers, who may know someone. be aware, any agency that wants to charge you money for a portfolio is to be avoided - a reputable agency will put you on its books for nothing, if they think you have what it takes. So beware of sharks - take someone with you for each new session.Good luck.
yeh i was accepted as a model about a year ago by models direct they are the biggest agency in europe give it a try and see what you think. good look! x