Hello, my name is Ben and it is my pleasure to assist you with your question today.
Employment agencies are prohibited from charging workers fees for finding them work. However, if the fees are not related to this then the agency is free to charge you these fees as long as you are told of this in advance.
There is a potential conflict though and this is due to the following regulation:
You will see from the wording that the agency cannot make the work finding service conditional on you taking up a service which attracts a fee. So it can be argued that by offering you work they have made it conditional that you get paid by them which attracts an obligatory fee and this could be in contravention of these Regulations.
It is a bit of a play on words and will come down to a strict interpretation of the wording of the law but it is an argument you can raise with them. The issue then becomes one that as you are not actually guaranteed any work by them they can easily refuse to use your services and offer you work in the future.
Please let me know if this has answered your query or if you need me to clarify anything else for you in relation to this?