The entire EY recruitment process was quite standard: application form, personality questionnaire and SJT, numerical and verbal testing, telephone interview, assessment centre, and final partner interview.
The partner interview was kind of tricky because it was hard to prepare for. EY only gives out standard information about the presentation they want you do; the rest is up to you. The interview experience can really vary for different applicants because the partners can do and ask whatever they like; seems like they don't care much for HR. I believe all interviews contain the standard questions about why EY, why your role, why you, why this location etc etc, but the rest can and does vary a lot.