“The monthly rent to be paid during the extension period is market-related rent that has been agreed in writing between the parties, failing which the subsequent agreement, rent and escalation rate will be set by an independent expert. That independent expert shall be appointed by written agreement between the parties and, in the absence of an agreement, by [the [Chief Executive Officer] of the South African Institute of Values. The lease provided, in clause 6, for an “extension period”, which provides that when the tenant attempted to exercise the second extension option for a third period of five years, the lessor stated that it was authorised for the proposed extension at an agreed rent of R150,000 per month plus VAT. In response, the tenant claimed that a fair rent represents an escalation of 8% per year compared to the rent that prevailed at the time. .