The Lead Tenant
The Deposit Schemes require a Lead Tenant be named on the Tenancy contact details. This can also assist you for should there be multiple Tenants named on the Tenancy and there be a dispute over damage you DO NOT want to be debating with different Tenants. Therefore one Tenant is nominent to act as the tenants' representative.
Your Tenancy Agreement should contain a clause such as ours
The Lead Tenant – Where there are, multiple Tenants the first named shall be the representative to act on behalf of you all jointly and individually when dealing with the Deposit. Another of you can replace the Lead Tenant, so long as we are notified in writing by a majority of you. If no Lead Tenant is specified then the first or only named Tenant shall be the Lead Tenant.