Give them hell! Had a recent dealing with them regarding flights to US and Canada, their own shite lost them a booking worth five grand.
Had to give them some pointers to their own terms and conditions. Seeing your predictament - you may wish to point this out to them - its in their own terms and conditions:
6.2.1 We will endeavour to assist you if you need to alter your Booking made through either our Telesales Service or our Retail Outlets for a Package or Other Holiday Arrangement.
6.2.2 Before we have issued your confirmation invoice, you may make alterations to your Order for a Package or Other Holiday Arrangement free of charge so long as you notify us of the required alterations together with your booking reference number, through the relevant Telesales Service representative or the Retail Outlet representative through which the original Order was made.
7.1 You and/or any member of your party may cancel your Booking at any time providing that the person who made the Booking communicates the cancellation to us in writing to our Customer Services Manager at the above address. Since we incur costs in cancelling your Package or Other Holiday Arrangements, the following scale shows the minimum charges that we will apply, based on the day your written cancellation is received by us and whether your tickets have been issued.
Cheers mate, sadly, it looks like those points you listed above apply only to retail or phone booked flights, not online. They are not backing down, but then I doubt management have read the emails yet, hopefully I'll get a reply tomorrow, along with an apology at least! Cheers
Get back on their site and go through their terms and conditions, those three points were just a few of them. As you know where you could stand by the time they get your email. If your situation ain't listed, you may find yourself in a better position than you think.