The first interview is with one person and is very focused on your cv, asking about why you chose your course, uni, specific modules. If mentioned any knowledge in any areas such as coding, they will ask a few questions in that area. As well as that there are the usual compliance based questions. As long as you speak clearly and truthful ( if you don't know a answer, say you don't instead of making it up), you should be fine.
the second interview is with 2 people. You first have to do a 10 minute presentation, on a technical subject such as your dissertation. Keep it a maximum of 10 slides. then a case study and the rest of the interview is pretty much like the first,
the case study, they expect you to do most of it yourself, one of the areas i failed was i needed a lot of guidance.
My case study was the British fishery commission wanted to track where all the British fishing bouts where fishing, to make sure they weren't going into no go areas and track this for 10 years.
one solution: have a gps and transmitter on every boat to transmit the boats location every hour.
you need to know a bit about binary code in terms of the size of the signal and its bandwidth.
to take into account interference at the star of the signal start off with a piece of the signal that tells you how many '1s' are in the signal.
Also i was asked what sort of system i would need, 10 years of info would be 10gb of data, so no normal home pc could be used.
you also have to mention other possible solutions, pros, cons, system interface
So hope this gives you a idea of what to expect.