There will be many other students looking for accommodation in London. Upon acceptance of your place you will be added to a private Facebook group where you can chat to each other and find out who else is looking for a place to live.
When you move to London, do not under any circumstances transfer money to a landlord without having met them first, or their letting agent and seen the property in question. There are a number of people who run scams where they advertise properties that don’t exist, and ask for rent or deposit upfront by Western Union or some other sort of money transfer means. These people are operating illegally – you should never send money to anyone unless you have proof that the accommodation they are advertising exists and that the landlord is legit.