Hiya,

I'm coming to stay with you for 3 weeks from the 5th of July but my flight actually arrives on the morning of the 6th. I have no problem paying for that first night but I won't be checking in until the next day (Mon) - is that going to be ok? Thank you.

That will be fine, you may check in any day; do be aware that you will be charged for the entire week starting on Sunday, as weeks are not prorated. If you are unable to check-in to the dorm until Wednesday or later, you must call the dorm and inform them of your late arrival date so that they do not cancel you as a no-show.