Clob,
A valid point however the biggest problem I found doing my IR from Cranfield was finding beacon slots. With the best will in the world they fill up rapidly and organising the slots takes far more time than planning the route.
On the day, the route is entirely down to the examiner and if they want a particular route or not it's their decision. Fundamentally there are also a limited number of airfields you can reach going there and back and the G/H section in 2 1/2 hours or so each test takes. I suspect most of the routes from Oxford or Bournmouth will have all been practiced several times by their respective students.
Just my thoughts.
VFR