It just didn't install. I did receive a message, which I can't remember now, but it did advise that there was some incompatibility between Lastpass and Opera.
Thanks for the attemps to help leocg. I only installed opera as a trial, to see how it was, and have decided not to persevere with trying to add Lastpass to it. I have been using Firefox very happily for many years and have decided to still use it as my main browser.
Will probably keep Opera on my PC for general searches though.
Regards,
ducatiman