heliheaven
If the same rules apply for helis as they do for fixed wing you need to speak to the CAA licensing department. They can tell you and give you the appropriate department in the offices in London or as you say you hold a FAA licence you need to speak to the appropriate department in the FAA Traffic rights/licensing
If you are taking payment it may you need to find out the ins and outs of private hire as you are freelance
I will PM you the bible reference for any operating rights
TnT