Wordfence not finding adware

A customer reported that their virus scanner is reporting that my website is not safe. I used sucuri.net to check and it says I have Known javascript malware: rogueads.unwanted_ads?1 from dolohen
I’ve had Wordfence installed since December and it hasn’t picked this up. I’ve run a high sensitivity scan and it isn’t finding anything. Can anyone help? I need to find which file the frame has been added please.