Great news: the bug I spent the last 30 minutes trying to fix was actually the lease-reader doing its job properly!
Bad news: potentially hundreds of tenants are under a Moorhouse Properties lease which states that consent to sublet shall not be *reasonably* withheld (as opposed to *unreasonably* withheld, which is certainly what they intended).
The lesson in all this: if you don't want your landlord to come to you in a zebra costume and declare, via rite incantation, that your classmate shall not be granted the tenancy because [zebra bark], then please, for your own sake, show your lease to a computer before you sign it.
Fun fact, if you google "not to be reasonably withheld" you find this error all over the place, including in public records. As far as I can tell it is always a mistake.