That is what they look like under office lighting - they both look brighter outdoors.
I then modified an existing photo of Fenchurch to simulate roughly what she would look like in each colour.
Here is the original photo:
Here she is in Trafalgar Blue:
Here she is in Royale Blue:
What do you think?
Update: OK, so the consensus (both here and elsewhere) is overwhelmingly in favour of Trafalgar. I do still love Royale Blue but I think maybe it's a bit too "rich" for a Moggy - I reckon it would look good on an old sports car or a Rolls or something.