I think Pol Pot should be accepted for Pot! Lots of people know him by his full name, and Pol is the family name anyway. Conversely, Peter didn't work but St. Peter did.
Putting the full name in doesn't seem to work (at the moment, maybe the setter will change?), I also got caught out with him. But I enjoyed the range of history included!
I had exactly the same two problems. Tried Pol Pot, didn't work, figured I had the wrong person (although the dates lined up but *shrug*) so never tried just Pot. Then the same thing happened with Peter.
A little grumpy when I saw the answers.