In case anyone else is as confused as I was about Philippe de Segur's memoirs, I can now explain that 'Un Aide de Camp de Napoleon' covers the period from 1800 -1809, and 'Du Rhin a Fontainebleau' starts with the end of the Russian campaign and finishes in 1814, with a short bit on 1815.
They are also both available secondhand in cheap format, I have found the former in paperback, pub. R.Simon, Paris and the latter in hardback,pub.Nelson, Paris. I got the two off the internet for less than £10.
The only problem is de Segur's highly literary style - horrible to translate!

Susan