Date Slicer Won't Affect Column Graph

Hi,

I have a report with two column graphs on, I have added a date slicer but the graphs aren't being affected by the slicer. There is another slicer on the report which the graphs are affected by but not the date slicer for some reason. I have removed and replaced the slicer, I have also tried to use the Edit Interactions button to make the slicer apply to the graphs but selecting 'Filter' or 'None' make no difference. As you can see from this screenshot the 'filters and slicers affecting this visual' shows that the slicer isn't being applied:

Does anyone have any ideas on how I can get this slicer working correctly please?

Thanks.