OK, I got it back. had to dig into FF and found that I had two listing for 1p under tools/add ons. removed both, then reset the extensions in 1p and it came back.
Thanks, all, for your suggestions.
Allow me to introduce myself, my name is Stu and I'm one of the customer care team over at Agile Web Solutions, the makers of 1Password.
On behalf of everyone on the team, I'm really sorry that you didn't get a response after 3 e-mails, we try our best to respond to every question within 24 hours at the most. If you don't mind, so we can track down what could have gone wrong, could you drop me an e-mail at stu [at] agile.ws letting me know the e-mail address you used on the contact form and I can check our system.
Oh, and I'm glad to hear you got Firefox up and running again, the problem you were experiencing sounds like one we've had a few reports of where Firefox 'hangs on' to an older version of the extension, so completely removing it is the only option.
All the best,