If 120 volt, and since he has not as far as I saw actually found it was 120 volt, then it was rather good being able to work with nearly twice the design voltage.
I have received a number of items with USA style two flat pins, and first thing is check voltage, all have been 220 or 230 volt, so having a USA style plug does not mean 120 volt.
I did find UK site with it listed, but no voltage, and says currently unavailable. It does seem likely it was 120 volt, but we can only assume. I tried to read package to find voltage, however could not find it listed anywhere on a site which is UK based.
What worries me, is not it may be 120 volt, but there is nothing to say what voltage it is.