Yes. All contractors are entitled to challenge an end hirers IR35 Status determination. To do this, they need to undertake an independent review and put forward additional supporting evidence.
As part of the IR35 assessment process all end hirers are obliged to offer contractors a clear process for challenging end determinations. This challenge process can be initiated either by the Fee Payer or the contractor themselves. Once started, the end hirer has 45 days to inform the worker or Fee Payer whether the decision can be overturned or not. If it can they need to provide a new SDS with supporting information in that timeframe.
If the end hirer fails to provide a response to either the fee payer or worker within 45 days, they will become legally liable for calculating and making the deductions for employment taxes from the fee payer to the end hirer. It is therefore important that this process is managed effectively by the end hirer.