Lancashirelad

Just 5 minutes spent on Google reveals that this is a common issue on many auto Fords for at least 10 years. Try pushing the selector lock switch in a few times also engage gear slowly. . I also found: " Turns out it was the transmission range switch which required a new circuit board" though that wasn't for a Ranger. From what I briefly read (which you could have done) it seems its likely to be transmission lock switch, wiring to it, connector, or the above.

Are you sure its locking after a set time, or is at a minimum speed? (more likely)

Thanks for the explanation. I guess you had meant to say bike and car licence.