Iris approaches Company A to be her insurance underwriter to transport 10 FCLs of PlayStation 5s valued at US$60M. Company A in furtherance of its underwriting, reinsures its risk with Solid Financials, a reinsurance insurance company. Iris containers suffer damage while on their way to Mexico. She claims on her cargo insurance and the insurance underwriter pays out the policy in accordance with the value of the damage.

Iris later learns of Company A's insurance contract with Solid Financials and demands to benefit under that contract. She retains you and request that you allow her to benefit under that contract.

As a Maritime Re-insurance expert, explain to Iris:

1. What are the principles that a marine reinsurance contract is based on?
2. Also, explain Proximity clause and insurable interest.

Please supply references.