Knowing the NICEIC if its them, then worse case scenario unless the install is really really bad is they will arrange another assessment visit in due course once any issues have been rectified - for another fee of course.
They do like to get you to do your RFC tests though and you could risk it but if they ask you to test that circuit you are up the creek without a paddle. dont try and blag it, you have time before Saturday to sort this but need to get working and to be able to explain to the assessor what you have done and the reasons why. let us all know the outcome.