Gearbox problem?

The gearbox on the Discovery has developed a strange habit of late. It’s quite weird as it only happens if you’ve been travelling at 60-70mph, in 5th gear for 15 minutes or more. When you come to change down, the gearstick becomes very stiff and hard to move making gear selection difficult. I’ve changed the gearbox oil but unfortunately this has had no positive effect. It’s booked in to the main dealers on Monday for investigation, let’s hope it gets sorted before the warranty expires!
To be continued…