What percentage of people with the name mohammed have their driving licenses from outside of the UK?
Probably not many. You can only drive on a foreign licence for up to 12 months and then (if outside the EEA or a citizen of a reciprocal country*) would need to pass a driving test to get one.
You can't just come from the middle east (for example) and get a UK licence without first passing the standard driving test.
*The list of countries with which Britain has reciprocal agreements includes: Australia, Barbados, British Virgin Islands, Canada, Falkland Islands, Faroe Islands, Gibraltar, Hong Kong, Japan, Monaco, New Zealand, Republic of Korea, Singapore, South Africa, Switzerland and Zimbabwe.
https://www.expatica.com/uk/moving-to/Exchanging-your-drivers-licence-in-the-UK_107710.html