They are a well known and good agency. Most of their clients attend the stage school but you can also join via audition. The costs are around £150(ish) which covers the cost of the Spotlight entry together with the headshots. They have a lot of children regularly getting work through them. They are quite a large agency as opposed to the boutique ones who have a very small client base. They are very approachable so probably best to give them a call.