how come the spelling changed from hurdy gurdy to hurdy girdy? or am I misinformed about the correct spelling?

btw English Jon is, by the description of him, Jon Loomes. Book him! a very fine musician with crazy taste in trousers (unless you've stopped wearing the parachute pants Jon?) I tried to find his website to link in but www.jonloomes.com doesn't seem to have a page attached to it yet...