Sipsworth by Simon Van Booy

Following the deaths of her husband and son, Helen Cartwright returns from sixty years in Australia to the English village of her childhood.

Her only wish is to die quickly and without fuss. Helen retreats into her home on Westminster Crescent, becoming a creature of routine and habit. Then, one cold autumn night, a chance encounter with an abandoned pet mouse on the street outside her house sets Helen on a surprising journey of friendship, and a way back into life itself.