It is always advisable to ensure that the names of all parties on the tenancy agreement (both the landlord and the tenant) are correct before signing. OpenRent users can correct any errors in their name by logging into their account.
That said, in many contracts it is normal not to include an individual's middle names or worry about extremely minor discrepancies, and this does not invalidate the contract. The most important thing is for it to be clear who the parties to the agreement are; ultimately the courts could, in the event of a dispute, make a judgement about the underlying intention of the contract, i.e. who was intended to be named as a party to the tenancy agreement.
So the crucial thing for both parties is to ensure it is not ambiguous who is referred to on the agreement. In most cases, the actions of the parties and other context should make it very clear who is involved in the tenancy agreement, so this is unlikely to be open to dispute.
However, landlords should take particular care about ensuring their own name is completely correct on the agreement (to prevent any possibility of challenging the validity of eviction notices, for example), and especially so when signing on behalf of a company.