My son found Bucks harder. He looked mentally and physically washed out afterwards However we received the Bucks results and he did very well. His tutor said that brighter kids will often come out with higher scores when the test is more challenging. He also sat the Slough/Reading test (at RGS). The general consensus between the kids seemed to be that the Slough/Rdg test was easier. It's these results we are waiting for. He is refusing to go to bucks and has pointed out within 8 school days he would spend 24 hours on a bus. He has a point.
Your Ds sounds very sensible! Can I ask why you entered him for an exam which would require such excessive travelling? Were you planning to move?
We were avoiding putting all our eggs into one basket. Had he not have done well at the RGS test I would have given very real consideration to the commute. We live right on the bus route to bucks. We also ticked for Rdg to share results with Slough with the same thinking. As it gets closer to the time the practicalities become more real, mind you.