Q: 'NB' = ?
I see that abbreviation often here, but don't know its meaning. Looks like it's used similarly to 'p.s.'.

To the topic, the presenters of this gala are spinning their affair as "a reenactment of a generic 19th century naval battle that just happens to coincide with Trafalgar"?

Pretty thinly-veiled spin, it seems. Must be another one of those Brit-irony things.