A. P. L. of the Shipley Times and Express praised the book, writing, "Besides mystery, there is a strong and continuous element of fun in the story contributed largely by the steadily plodding Ern and the irrepressible Fatty.
"[2] The Morpeth Herald said, "Two runaways, a stolen picture, a little white poodle, and the Five Find-Outers and Dog on the job; these are the ingredients of this splendid yarn.
"[3] Writing for Enid Blyton Society, Robert Houghton called the book a "fine tale, involving a stolen painting and its whereabouts".
As an eight- or nine-year-old child, he was going over The Mystery of Tally-Ho Cottage and found himself in the boy Frederick Algernon Trotterville (FAT) who gets nicknamed Fatty.
[5] The manuscript included Blyton's handwritten statement that she typed her stories "straight out of my head" rather than penning them via hand.