After doing a search on these pages, I installed the latest version again - over top of the existing one.
For the moment, it seems to be running properly.
I did notice that the icon of the irremovable version wasn’t that of the Mozilla fox, but more of a ‘file’ type thing, both in Programs and Uninstall Wizard.
I’d still like to know about the Trojan if anyone has the time to help.
Thanks for reading,,,,,