I will keep this brief...
No.
They have no other recourse - that is the whole point of putting them in at zero - to show the Contractor they have no liability and therefore would no doubt have given a cheaper tender price accordingly!
Had they not have included X7 at all, then they could have claimed for losses incurred in a court of law but outside of the contract. By setting X7 at zero they cut of that legal right.
No.
They have no other recourse - that is the whole point of putting them in at zero - to show the Contractor they have no liability and therefore would no doubt have given a cheaper tender price accordingly!
Had they not have included X7 at all, then they could have claimed for losses incurred in a court of law but outside of the contract. By setting X7 at zero they cut of that legal right.