Disputed refund to Commercial licencee

[250GTO]

We are a UK Ltd company and granted a short term licence to occupy our premises (to another UK Ltd company). The licencee was a UK Ltd company, from the start. We were told to invoice the same uk ltd company for the fees (rent). The same Ltd company paid all the subsequent licence fees. When the company moved out, the condition was not as was stipulated in the licence and repairs were necessary. We have an estimate for the repairs which exceed the deposit. We made a proposal to meet and inspect the damage. We also made a financial proposal to compromise. Both proposals were rejected. A county court claim has now arrived - but the action is brought in a different name (to the UK Ltd company, the 'tenant'). It's not the original (or a) Ltd company; it's not a personal name - but is a businesses name (ie. not incorporated). When we respond, should our initial defence be that we do not have any commercial relationship with the claimant (and from whom we have received nothing) or continue with our defence and counter claim for repairs?