"In view of the next quarter rent payment, I attach a draft invoice (and side letter) ... pls do not consider this a final invoice because I wanted to first discuss this with you when we meet on Friday."
"If you breach any of the terms and conditions contained in this agreement or any term of the Lease and/or any document supplemental to it (for example a licence to alter), we may terminate this agreement with immediate effect and the rents will be payable in the manner set out in the Lease as if this agreement had never existed...."