The next challenge will be to see if the Renault dealer accepts that the original was "not fit for purpose" and will pay for the replacement!
This website (Towball Height
) quotes From the Caravan clubs handbook page 640 (1999 / 2000 edition ) it says the coupling ball is 50 mm diameter and when measured from ground to ball centre should be between 350 and 420 mm (vehicle fully laden - but not with caravan attached) in accordance with BS AU 113c or ISO 1103.
I think Renault will only refund if it's below 350mm fully laden.
Just checked the Modus and it's about 380mm unladen, but it only tows a small trailer, so it's not a problem. (Don't think I'll be trying to tow a caravan with it - probably easier to tow the Modus with a caravan.