Before a phone interview, they called you to arrange a phone interview and told you what questions to prepare. Then a 20 mins phone interview, asked about basic questions about yourself and why you want to get in investment banking industry. Get an pass email on the same day. Two days later, they called me to arrange an assessment centre day. Every Monday has assessment centre day in London. 9 am-3 pm for an assessment day. Just follow the guide book they provided for the assessment day will be fine.