I admit, it looks off and I thought that when I first saw it. That's why I said I'm not convinced it's genuine. However, when I compared it with exemplars, I thought there might be a case for it being an unusual but authentic autograph. The 1974 TLS is a very odd signature. My point was that if the TLS is genuine, it's possible the OP could be as well. Judging by others feedback, I'm off the mark with this one ....
Here is a genuine John signed in 1975. Some similarities, with the John part of the autograph in question. I am not happy with the autograph discussed here. Or could it be that is because it is signed in crayon.