Loopy ✭

Hi Gjoksi & Alexandru_BD Thank you for your replies in the end, as I am somewhat time constrained, I elected to refresh my Firefox browser, after which I was able to re-install Password Manager and all is now working as before.

Update: I have been able to find a site with previously saved passwords on Chrome and re-activated the little red security icon in the username dialogue box, so Chrome is now working again. I am still unable to re-install Password Manager in Firefox.