I had a Nuttal bred bitch that was same,show her a hole n she was'nt interested but show her the end of a dig she was like a dog possesed,next day show her a hole with one in n not interested again,i'd like to say she eventually took to it but she never did,it was down to bad breeding,but you sometimes get well bred uns that dont make it,thats terrier work for,it'd be boring if they were all world beaters,but its a shitter when you get a duff un,but like i say i'd give it a bit longer before you write it off