What is the difference between joint and composite insurance?

In your document 'Insurance in construction and engineering projects', you say that all risks insurance will be "In the joint names of the contractor, the employer and any other party with an interest in the project, for example, a funder of the project". However in your document 'Insurance contract law: general principles' you say that "Joint insurance exists where two or more parties with individual interests in the same property take out a single insurance policy. A typical example is a husband and wife jointly insuring their home" whereas composite insurance "exists where two or more persons with a separate interest in the subject matter of the insurance, are insured parties in the same insurance contract. A typical example would be a mortgagor and a property owner or a contractor and sub-contractor."

Where we are acting for an employer or a funder we are being offered composite insurance by the contractor's insurer not joint insurance and on the basis of your document 'Insurance contract law: general principles' that appears to be the most appropriate insurance to obtain for our client. Please can you clarity.