Be yourself.
I would also read as much as you can in English until the interview. Look for new vocabulary that you think it may help you for the day. Read your application (the answers you gave) hundred times. Have a look at the requirements and all the info about the job since you can find many words that you can use later on your examples. Bonete talked about this already on his post. Words as outstanding, etc.
But above all, be yourself. Practice at home the answers loudly and speak a lot in English before the day.
I understand that you are in Spain currently, hence I told you to practice the English. If you are in UK you won’t need it!
I’ve got my interview on the 3rd Dec and Im nervous as well.
Good luck! When is it the interview?
Saludos