Wedding insurance is something that a lot of people overlook because they are so optimistic about the future with their new partner that nothing can possibly happen. Wrong. Even though your suppliers will have their own insurance, you did check that didn't you?, you still need your own cover because you cannot control outside circumstances.
Once you have started paying those deposits, get insurance. Remember to get a magnify glass to read the small print and ask what is not covered, try to get the exclusions in writing with large print! That way you will know what is and is not covered.
It may be an extra expense but if things do go wrong you will be glad you have it.