I sat down last night and went through the whole shooting procedure from start to finish but with no film loaded (I didn't have any around I was willing to sacrifice) and it worked perfectly a dozen times in a row.
Might simply be a process of me learning the quirks of an older, fully mechanical camera in order to avoid the problem.

Tammy: I'm glad I'm not alone I will take careful note of how I place the top spool next session. I am going out shooting with it this Sunday so will know more after that.

Thanks to all of you for your help. It would have been a far more difficult troubleshooting process without your insight.

Ben