Thanks for that. Nothing seems to be able to uninstall the current version. I have tried from Programs and Features, I have used the same installer that is currently installed (13.4) which offered change, repair and uninstall, none of which worked. I have also tried the latest v13 from your download link and v14 from your link. All of them come up asking for SmarterMail.msi:
I would like to add some screen grabs but I don't have permission to. Try and guess them from the following:
threews waxwing.co.uk forwardslash images/sm/error1.png
threews waxwing.co.uk forwardslash images/sm/error2.png
Not quite sure what to do at this point. I will try installing that exact version on a test system to see if I can regenerate the files that it wants in order to uninstall. I have always uninstalled before reinstalling, but as that didn't work this time I thought I would give a new version installer a go to see if that worked.