She could be independent or work for an escorts agency. You can book on the same day you require the services or book even a month earlier.
It is advisable to book earlier, especially if it is a reputable agency.
You will get more than just companionship when you book an attractive woman from the agency.
If you are a person of high status you better go for escorts in London instead of a date because they know how to act in an environment with people of high standards.
London Escorts agencies have well educated sexy women who can hold intelligent conversations about any subject with those around you.
They are well trained to make you feel comfortable in the city.
A date on the other hand might not be familiar with all areas in the city or might not be available to show you around when you have time.