@Nicki20
The simplest but perhaps not the best solution for me was to just block Ultra Peak dates on the site and have them available elsewhere. For me the biggest reason was that these dates on other sites are immediately prepaid to us at the time of booking and non-refundable.
Christmas is usually booked out by the end of August and if we rebook we can refund but many people book really far in advance for these dates so the closer you get to arrival, the fewer guests are looking. I prefer not to work within the limited cancellations and payment policies on offer here for peak dates.
If you want a flexible policy for the bulk of the year you also have this policy for peak dates so short of setting up a second listing with the different policies, I felt it was better to just not offer these dates.
You could also just move your weekly window forward by 6 or 7 nights if you wanted to and when peak dates book then change it back to your regular minimum night stay. Not optimum but it should work.
As for cancelling a guests booking, you will incur a financial penalty for this and not have the dates open for booking. This is a really big no, no. Perhaps you should snooze the listing while you familiarise yourself a bit more with how things works so it does not cost you any more money!! You can try calling customer support and see if they will give you a first time user pass on this but don't count on it. You are supposed to read about all this before you go live.
Lisa
PS The support number for Australia is 02 8520 3333