Hi gulliver,
Sorry about my earlier post. Have been on the web too long tonite, and was getting your original post confused with someone else's regarding XL.
I think you will find that Goldtrail are showing the increasing levels of pricing, dependant on how many people you are looking to book for. They probably have a limited number of seats available at £269, and as soon as these are gone the price will rise to the next level and so on. This is what lots of operators do, but without the transparency shown on Goldtrails site. If you are happy with the price I would book sooner rather than later, unless you are willing to take the gamble of a last minute bargain?
Hope that this helps.