Had a chance to do some research on Napier engines today.
The Sabre, Rapier and Dagger were so named due to the proximity of the Wilkinson Sword factory in Acton.
It's also due to Napier that we have "British" Racing Green as it was their car winning the 1902 Gordon Bennett trophy in dark green paintwork that started the trend!
Don't mock, you may very well win a Quiz Night with that sort of info!!