Calastone do not have, nor have they ever had an office in Birmingham. They also don't have an online application process. I think you have not got the job interview you are describing because, for a start you obviously do not know the name of the company you applied for!
With a dictionary of words provided in the form of a list, and given 7 random letters, write pseudocode to determine which words can be made from the dictionary (list of words) from the letters given. a.k.a. the game of Scrabble.