Powerpoint code works in Template, but when a new document is created, the macros don't function.

I have been writing VBA code for years, but mainly on Word and Excel. I now (because I am now teaching) have been moving onto code Powerpoint to do some awesome things like live text editing in a lesson on a slide in presentation mode and shellout out to external apps like Calc and Audacity, but my problem has been with creating code that helps me create slides.

When I work on the Master .potm (Macro-enabled template) the code to create slides, title them and add an appropriate graphic / shape chosen from a Ribbon dropdown all works fine. However, when a .pptm is created from that template, the code doesn't run.

Any insights or suggestions please?