the little black rubber weather proofing seal at the throttle end came off the outer cable and jambed up the throttle as a was zipping along

Required quick thinking to kill ignition, and glide across three lanes to roll up to the Mercedes dealer driveway

Lucky mate! 

My mum had the same issue in a Range Rover classic coming off a freeway. The throttle wouldn’t release from cruise and she put it into a ditch where she went flying out the other side.  This landing released the issue with the throttle and she was able to pull the vehicle up. 

Damage: shock! Front diff housing was bent and one king pin mount stretched by at least two mm. The rear of the chassis was bent when the rear bar contacted the ditch when the car dragged its arse through the ditch after the front end started up the other side. 

Bloody scary! 

Glad yours was an easy fix and not a major issue Jono!! 

Cheers 

Bennie