The First Doctor, Ben, and Polly

For quite some time, poor Anneke Wills was a bit stuck. She was up for participating in Big Finish, but Michael Craze had died in 1998, and there were no stories with Polly but without Ben. Some Companion Chronicles were possible, and she did a few of those, but they mostly focused on the Second Doctor era, probably because Frazier Hines is always up to play both Jamie and the Second Doctor. Eventually, though, Big Finish recast Elliot Chapman as Ben, and although the focus is still on the Second Doctor era, there have been a few later Companion Chronicles where Polly and Ben are traveling with the First Doctor, which takes us right up to the end of this era.