The whole process took about 7 weeks, from an initial HR call through to the final interview.
First I spoke to a nice man called Alex who asked me the usual questions, explained the role, and passed my details on. Then I had a Skype interview with the European manager, which was about 20-30 minutes and went very well- questions were much as I expected- why do want this role, tell me about your current job, why are you leaving, tell me about a time when...., and so on.
I then proceeded to the final stage, which was at the Birstall site from about 9am to 2pm. It was in three parts- a fact finding interview, a case study and presentation, and then a competency based interview.
I was really impressed that everyone in the panel was a woman- I'd seen that Mars were working on their E&D through my research and it's evident. All were professional and friendly, it seemed like a great atmosphere to work in.