In the Parker Pyne short story The Case of the Discontented Soldier, Mrs Parkins is the landlady of Freda Clegg. She doesn't have any lines of dialogue and doesn't make a personal appearance in the plot. Major Wilbraham needed a postage stamp and a maid got one for him from Mrs Parkins, for which the Major paid a shilling.
Mrs Parkins does not appear in the TV adaptation of the story. There the landlady is named Mrs Benson.