Raffles,
I can only echo BL's post, do your homework, you have the benefit of the RN's website with a wealth of information and more importantly really current news of what we are doing.
Make sure you read around - not just aviation but also what the navy does, how the different helicopters/jets are employed as weapons systems etc - this will impress the board.
I also recommend subscribing to a publication such as 'The Week' which gives you an intelligent round up of current affairs. Jane's Defence Weekly would also be worth looking at.
I was in the same 'boat' as you having been RAF-centric until university and found that a few days on a frigate opened my eyes to what the RN was about, and more importantly what the ethos of the team you will be working with is like.
Finally, if you do go RN you must be prepared to be a chopper pilot (I wanted to). It's worth thinking about whether you would be happy with that. Although, providing you have the capability, I would think that with JSF coming on line I would think a rotary to fast jet crossover would be pretty likely.
The rumour are that shortly all 'Flight' (Pilot, Observer, ATC) joining Dartmouth will do so having been judges capable of flying JSF. Those who don't make the grade through the process will become Rotary Pilots, Observers ATC etc).
There is no doubt that the future is bright for the FAA and that with the current tempo of operations you will be quickly doing it for real somewhere.