It is important to make this initial appointment as early as possible - at least 6 weeks before you travel - as a second appointment may be required with the practice nurse to receive the full course of the vaccination. These vaccines have to be ordered as they are not a stock vaccine. Your second appointment needs to be at least 2 weeks before you travel to allow the vaccines to work.
The NHS has a very comprehensive website, giving the information you need to identify any vaccines advised for trips abroad, & ensure that you stay as healthy as possible. This can be found at fit for travel