Thanks all for your replies. I can see a general consensus that 30m would be considered plenty for the GLEX and i agree this would be plenty however...
Given that we have to comply with regulations of the country we fly to, many ICAO member states follow the minimum runway width recommendations as law. An example of this would be Australia which has it in the AIP. This is where my confusion lies. The Global Express has a Reference Field Length (based on a Balanced Field Length @ MTOW) of over 1800m which would require a 45m wide runway by Law even for N registered aircraft in countries that comply with this recommendation.
Or am I missing something?