Taking birth control while traveling out of the country

I am traveling to England in about a month. I live in the New York time zone so England is 5 hours ahead. I normally take my birth control at 9 am, so that is 2 pm in England time. Since I will be there for two weeks for school and I will be out and about doing activities for class in the middle of the day I was thinking I would just take it around 7 or 8 am (England time) when I am getting ready in the morning. But when I get back home after the two weeks I will want to go back to my regular time of 9 am. How long will I have to wait before it will be safe to have sex again? Any advice?