Hi Katie and welcome to SAAFE
You haven't mentioned whether you have read through the
main SAAFE site - this forum is just a small part of things, and should really be your second port of call once you've looked through the many articles there geared around helping you decide how you want to work and taking the first steps to getting started. There is information about law, health, safety and security, tax and pretty much everything else and also a search facility on the forum
here.
We don't generally recommend employing agencies here, because unless you have such a limited amount of free time you really can't spare even an hour a day for taking care of advertising, enquiries, arranging your bookings and so on, there is very little to recommend about the majority and even if you do decide to use an agency we would still recommend you do your own security checks for peace of mind, as a significant number don't actually bother no matter what they claim. There was a recent thread on a punting board where many posters commented that they always used agencies and had never been asked for personal details. You may wonder then why it's worth handing over a large chunk of your fee, and you'd be right.
If you would prefer to work with an agency, we cannot give specific recommendations on the public board, but there may be ladies who can PM you with a few ideas. In the meantime, please read the main site and if you have any more specific questions just bring them back here and we'll be glad to help!