Carol Anne Douglas's novel Lancelot and Guinevere, the sequel to Lancelot: Her Story, has been published by Hermione Books (ISBN: 978-0-9967722-2-8). In the sequel, the female Lancelot and Queen Guinevere face dangers that test their mettle. The books is available in print and e-book versions on Amazon.com https://www.amazon.com/Lancelot-Guinevere-Carol-Anne-Douglas/dp/0996772227/ref=sr_1_1_twi_pap_2?s=books&ie=UTF8&qid=1488396628&sr=1-1&keywords=lancelot+and+guinevere
Sherwood Smith, author of Crown Duel and many other fantasy books, says, "The poignancy of the end was far more satisfying to me than the doom in many Arthurian poems and tales. Altogether an excellent read."