Found out myself that it is infact possible to do this!
Using the techniques of the video above, but rather than swapping one line for another, we edit the line to point at the generic driver head.
For example, i changed the following line in all of the XML files referenced:
<part id="Driver::Head" mesh="eaid://character_package/heads/male_driver/lewis_hamilton/idf/lewis_hamilton"
to this:
<part id="Driver::Head" mesh="eaid://character_package/heads/male_generic_driver/james_faflick/idf/james_faflick"
the path to those generic heads can be found at F1 2018\character_package\heads\male_generic_driver, and then just pick the name you want to use.
I have noticed a slight glitch with the cap texture mapping, everything else worked fine. The cap worked fine with the recolour previously, hopefully someone can help with that.
I've only tested this as far as the career hub in career mode, but it works there too.