@portpass1974 - I used WP Rollback with no issues (all data was still present once downgraded)
@Joseph - I do really rate this plugin (it's one of the best that I currently run) and appreciate that the version I'm using is free (and that you operate on a commercial basis with the Pro version) - it's also great that you respond to posts here promptly. The point I make in my previous post is really that I currently have no fix for the free version and no way to upgrade unless I'm prepared to lose all of my data - as I say, a real shame as I think the plugin's one of the best I use.