ontour on "[Plugin: Wordfence Security] [WordFence] Can't update WordFence (or several other plugins)"

I'm running WordFence 5.0.6 and can't update to later version - each time I try I get an error message "Could not copy file. ordfence/lib/IPTraf.php". I'm having similar issues with three other plugins (special text boxes, shortcodes ultimate, and NextGEN Gallery). I've tried updating one at a time, deactivating all plugins, changing theme to 2013, but still can't get them to update.
I'm worried because unfortunately it seems that I don't have any recent backups. I've not done any massive changes to the site that I could pin this down to.
Any help very very much appreciated

https://wordpress.org/plugins/wordfence/