The commercial rent for the purpose of ICTA88/S782 is the rent, which at the time when the lease was created, might be expected to be paid, if:
Where the asset is not wholly used for trade purposes, the
commercial rent is the rent that would be paid for the actual
trading use.
Where ICTA88/S782 applies, the taxpayer should be asked for
their estimate of the commercial rent, supported by any available
evidence. Any case in which the commercial rent cannot be agreed
should be submitted to CT&VAT (Technical).