They confirmed there is space for three more teams to take their places on the start line in the French city of Reims on 5 July.
The route will cover six countries, including Switzerland and Germany, in three days. So far, 21 teams have entered the challenge, which features Not Just Travel and Holiday Extras as headline sponsors.
The event, co-founded and run by Beachcomber Tours sales director Sarah Archer, will conclude in a secret location on 7 July.