OK, this is a real shot in the dark, because I have no details, but hey, you have to try these things if you want to move forward.
about the turn of the 20C, a member of the Knightley family married a German lady and moved to germany. Thats the last we know of him and his wife.
So yes you've guessed it, I am looking for his descendants. there cant be many Knightleys in Germany... if they survived two world wars.
Anybody out there know anything?

Thanks in advance,
John Edwards.