265(2)Subject to sections 247, 256, 257 and to subsection (1) of this section, if the insured named in a contract has or places any other valid insurance, whether against liability for the ownership, use or operation of or against loss of or damage to an automobile or otherwise, of his interest in the subject-matter of the contract or any part thereof, the insurer is liable only for its rateable proportion of any liability, expense, loss or damage.