“The Landlord shall on each occasion furnish to the Tenant as soon as practicable after such total cost and the sum payable by the Tenant shall have been ascertained a certificate as to the amount of the total cost and the sum payable by the Tenant and in the absence of manifest or mathematical error or fraud such certificate shall be conclusive.”
“To pay the yearly rent reserved by this Lease at the times and in the manner required under clause 2.3 and not to exercise or seek to exercise any right or claim to withhold rent or any right or claim to legal or equitable set-off or counterclaim (save as required by law).”