Apple Ultra Watch not showing sunrise/sunset time

I have had this complication on my display for some time. Recently it has stopped showing the time, only showing some dashes. Having looked through previous comments I have tried switching the complication to a different one and back again then checking I have the correct allow when using setting on location services. The only way I can get the times displayed is to reboot the watch. After a few days the display returns to dashes. Anyone got a permanent fix for this?