Mary Berry (in-universe)

The Third Doctor once spent a summer in the Cotswolds on a narrowboat with Mary Berry. (PROSE: Twice Upon a Time) The Twelfth Doctor called the First Doctor "Mary Berry". (TV: Twice Upon a Time)

Infomation from invalid sources
Mary Berry was a chef who attended the Twelfth Doctor's 2015 Christmas dinner party for Sprout Boy when he was feeling left out. She later met the Twelfth Doctor and shared a Christmas cracker with John Luther. (NOTVALID: Sprout Boy meets a Galaxy of Stars)

She later assisted Eddie Redmayne when he contacted the Twelfth Doctor in the TARDIS. She acted as his personal cook. (NOTVALID: Looking for Pudsey)