Call the existing insurer and tell them you want a better deal .... they're likely to lop about 12-15% off if you threaten to cancel.
We have separate buildings and contents policies with the same insure 'cos it's less than a combined policy (WTF?) ... just reduced the contents by 14% against the renewal notice, waiting for the buildings renewal to arrive in the next few days when I shall be making "my annual phone call" as I told them !
Rob