Joe,
Sorry about that little outburst! It's something that crept in from other threads. Very interesting stuff about Boyd and Halsegreen. If you can find who had it in the first half of the 17th century (guess) it could prove even more interesting.

Regarding 'Fall', from Diva's post it would seem that the surname was well established before the Gypsies arrived. That some of them would adopt an existing respectable surname seems like a reasonable gambit to me. Of course intermarriage is also a possibility.

Michael, I would have thought that immigrants like these would quickly adopt any name they were being called and repeat it but I'm not going to argue with the OED!