lftp not removing remote files for me

I'm trying to download some files from an ftp dump site (one of our clients) and then remove the files once downloaded (using linux).

After some digging around I've come up with lftp to do the task and have the following script successfully getting the files

lftp -u  uname,pwd -e "mirror --Remove-source-files --verbose Recordings /OSQA/recordings" 203.zzz.fff.xxx

When the download completes, I get a message saying

158 bytes transferred in 4 seconds (891b/s) To be removed: 0 directories, 4 files, 0 symlinks

but nothing is deleted.

Any ideas what I'm doing wrong here? I need this to be in a script, so its a pain not to be able to get rid of the source files.

Thanks heaps

Peter.