Beware, if you don't have 8 participants, they just won't turn up. Happen to us a fortnight ago,
left standing on the pier waiting, they sent an email the evening before saying because we didn't have the numbers the tour was cancelled. We didn;t see the email until much later as we didn't have internet connection all the time we were on the ship. When I read the email, I replied to them, and was furious
and then I was threatened with a Law suit should I say anything on Cruise Critic or Tripadvisor.