Hi Pete,
look below, please, and say if I am right :-)
1)
I have FBF WLAN
GER firmware, Annex B
2)
I ONLY download .tar file (the one you gave link abowe)
3)
I logg in Fritz -> System -> Update -> ...browse......tar !!!
4) That's all !!! - I have F!BF WLAN - ENG firmware...