A verbal lease agreement is binding. However a written lease agreement is advisable as this protects both the tenant and the landlord in the event of a dispute. In terms of the Rental Housing Act, the tenant can demand the lease is reduced to writing.
The tenant is entitled to a free copy of their lease agreement. However if the tenant looses their copy of the lease agreement, the landlord (estate agent) can impose a cost to provide the tenant with a second copy