Seems like you are talking about three entities.. content, contacts,and approvals.
Approvers are a subset of contacts (specific type of contact)
I would set the approvals table to be a join table between contacts and content because a contact can be an approver on many content and content can have many approvals/approvers
Many thanks, I couldn't get my head round it, but I guess it's similar to an invoicing solution Ie products line items and invoice. so I'll create a new table for approvers.
I can crack on now