Hi Matty, have you checked the marriage :
Jul-Sep 1906 Toxteth Park 8b 483 McNutt John ? It may not be him, as in the death registers there is an entry for a John McNutt Oct-Dec 1906 Liverpool 8b 42, age 32, but if you have no further luck, it maybe worth checking.
Also, some McNutt's seem to have gone to the USA from Liverpool-maybe he did that?
Sorry I couldn't help further, hope you find him, haliared