Yes I did check the local PC.

We ended up finding the issue yesterday in the reportserver.config you need to change the CSV formatting as below. Otiginally it was set to False changed it to true and all good now.

<Extension Name="CSV" Type="Microsoft.ReportingServices.Rendering.DataRenderer.CsvReport,Microsoft.ReportingServices.DataRendering">

<Configuration>

<DeviceInfo>

<ExcelMode>True</ExcelMode>

</DeviceInfo>

</Configuration>