I can't help notice that when holidays are sold out, they are removed from the website, and anyone who may have the page bookmarked are given a message:
We're sorry but the tour you selected is no longer available. Please take a look at our list of similar holidays shown below, as we think you'll find an alternative that's just as inspiring.
This can actually be quite inconvenient for someone who has booked the holiday, and simply wants to check up on a detail, such as the itinerary, without rummaging for the posted confirmation (which may or may not have arrived at that point).
Wouldn't it be possible to keep holidays on the website, and simply mark them as "full", and prevent any further bookings being made for it? Obviously, once the holiday dates have passed, then it could be removed completely, but until the start date, it is really useful to have the details available online.