Pivot - Calculated Field

I have two fields, one called Call Date and Time - which is in format dd-mmm, and dayname which is text i.e. Mon/Tue

I want to combine the two as a calculated field in a Pivot table so i can display within a pivot chart.

I've tried many iterations, the latest being - =dayname&" "&TEXT('Call Date & Time',"dd-mmm")

But just get #value when I put it into the pivot table

Where am i going wrong?

I would have thought you could modify the field setting of your "Call Date and Time" field, on your Pivot, to use a custom number format of ddd dd-mmm

That has no effect

see attached

yeah that was a bit easy wasnt it!! Thanks