Joining Tour in Paris


I’m heading out on the Roman Road tour departing May 19th, however before I knew I was taking this tour I had already booked my flights. I arrive at London Gatwick at 11:45am and have to make my way from there to Paris to be able to join the tour.
Is there a major problem if I get to Paris after 5pm? Has anyone arrived late before? Chunnel times don’t appear to be in my favor that day.

Thanks! ::slight_smile: