FAO Alsacienne and Barry,
Thanks to you both for your help. My son returned safe and well last night and thank goodness, no sleeping in the car this time
He picked up the hire car as planned from CDG BUT....the sat nav was in French and there was no way (that he could find anyway) of converting it to English. However, he used the viamichelin route finder that Alsacienne recommended and found his way to within 5 mins of his workplace. He then phoned them and they sent someone to meet him. His hotel was about a 5 min drive from the workplace and had no probs driving back and fore. He was lucky on his return to the airport as a taxi was leaving for the airport at the same time as my son so he followed it and arrived in plenty of time. I'm one happy bunny
He'll be doing the same again a week on Monday when he returns for a week's training. Hopefully, I'll be more relaxed each time he has to do it. Thanks again, it's been good to share my concerns.