alliu SC
I hate to say this, but I think you might come unstuck as they plan the interview days for specific numbers of people, and bearing in mind they are execting you at 8.00am, its likely once they get back to the office to read your mails you are already a no show.
I would think carefully about your descision.
If this career is really for you, then the expense is not so much. Excuses such as being on holiday (you can access the message centre from and PC after all), forgetting the BH and deciding its to expensive to attend the interview dont bode well for your organisation and comittment to the role - which are both vital attributes. You have to be really driven to get through the college and validation.
I think not confirming your attendance would maybe be at worst a minor issue. Not tuening up on tuesday I think is a big no no.
All of the above are just my thoughts you understand, and i wish you all the best, but you did ask...