I am now totally confused. I don't think I need to get involved in the discussion of contacts vs customers, I have already dealt with the issues of a single company having several different contacts and I understand this issue. My problem is that for a single enquiry (where a single contact can make several eqnuiries) the one enquiry can related to several staff, who would be selected via a portal on the enquiry page.
I think I should have the table Enquiry, representing the entity "Enquiry", with the enquiry attributes, a join table "StaffEnquiry" and a Staff Table to allow for the many to many relationship of one enquiry having many staff and one staff being able to work on many enquiries. The staffEnquiry Table would also allow for fields such at amount due etc. Am I along the right tracks?