Thanks for getting back to me.
I have reset all passwords the first time this happened a few weeks ago so that has not helped. No odd user accounts in word press or ftp.
I dont have a local copy of the site and the host only keeps 20 days of backups and I know the first time this happened was over 20 days ago so i dont have an option to restore a clean copy.
I dont unerstand why WordFence and other scanners i have used detect no malware but if i use Imunify in Cpanel it detects more and more with every scan, its obviously continuously replicating. And becasue WordFence isnt detecting anything i cant repair or delete the files.
Have followed as many articles as i can find but nothing seems to be a permanent fix.