You were right Sian. I have corrected it. It was me forgetting music theory. The music I copied from gives a Db as an accidental and I made the next D a natural, forgetting that the bar would have needed a natural sign to cancel the previous accidental.

A question for those who know about modes: The tune I copied is in Eb giving the Db as an accidental. If the tune is mixolydian, wouldn't it be more correct to show 4 flats rather than 3 in the key signature?

Jon