Company background -
Rolls-Royce web site. They have a whole section on DA, which should address what they're looking for. Also, look out for any recent press coverage, note: they have a 'media room' on their web site, and try Google News, for example
this.
Recent engineering project - the ones you mentioned seem OK to me. Anything directly related to the position your in for would be very impressive. Did you participate in any of those engineering schemes (sorry, don't know the names).
Gas Turbine – you could try to dig deep with this and away from the usual facts attempt to find out something unique. Or this could be an opportunity to pose a few questions at the interviewer – showing your interest and enthusiasm.
Pieces of paper would be fine I imagine – diagrams and anything to further illustrate your research would definitely be helpful.
Demonstration of laptop – I’m neutral on this, not really sure. You could always prepare it and see if it’s relevant at the time.
And of course cover the usual interview grounding: strengths, weaknesses, why you opted for a gap-year, what you want out of it, career aspirations, examples of team-work, leadership, initiative, etc.
Out of curiosity, is this job interview through Year in Industry?
Best of luck
