When is deposit and first month's rent payable?

The OpenRent contract states,
2. The Tenant shall pay to OpenRent on the signing of this agreement the amount of the Deposit and the first payment of Rent, unless the Tenant and the Landlord have agreed in writing a later date when payment may be made.
Are these amounts payable when the tenant signs the contract (the tenant signs first) or when both parties have signed?

Hi Stuart, it’s when both partes have signed.

Sam

Thank you, Sam, and for your quick reply. Would an improvement to the Contract, to avoid ambiguity, not be:

The Tenant shall pay to OpenRent on the signing of this agreement by both Parties the amount of the Deposit and the first payment of Rent

Thanks and best wishes, Stuart