As far as I know, there is only one other Insight in London. Interestingly, this person works or lives about 2 blocks from where I work, so I see it fairly often. I have been told the owner is female, but I have not yet met her. People always confuse the two of us as we both have long black hair and both drive silver Insights. I just tell them "you can always tell me because my rear wheel skirts are not attached in such a sloppy way".
Have not seen any Prius' as of yet.