Actually I think I can do this by adding a new resource, matches, and then defining that within the fields eg within the Bookings resource I have the following:
HasMany::make('BookingMatches'),
I will give that a go, and maybe I have answered my own question ;)
OK - no, this does not work. I need to be able to run a specific function when linking to the matching resource, its not a direct field match. It's radial and based on other fields.