Hi Drewpat,
I don't see there being a problem with this. However, the holiday price is based on limited availability special air fares, by the time you book we may have sold out or released them back to the airline. In this case, further seats are available at a supplement. We do always advise that the earlier you book the better, so you can guarantee your place.
You could give us a call, using the phone number in the top right hand corner, to see if we can do anything for you.
I hope this helps.
Kindest regards,
Monty