Right I have got my stuff mixed up yet again, but now I have 2 theories.
You Only Live Twice...
Bond arrives in Tokyo and gets taken to see an informant Mr Henderson (who gets assassinated during their meeting by a knife in the back)
I am sure its the same actor who acts for the part of Blofeld in Diamonds are forever?
MY SECOND THEORY
In You Only Live Twice, Donald Pleasence plays the dude of Spectre #1 (guy with the cat), his name was Stavro "Blofeld"
In Diamonds are forever the villians name is "Blofelt"
Discos - any sense to you, its bassically asking if they used the same actor AND did they prtray a family connection with spectre and diamonds are forever for Bond's return
There's nothing sinister about it.
"From Russia With Love" has a full-head of hair Blofeld
"Thunderball" has a full-head of hair Blofeld
"You Only Life Twice" has a bald Blofeld
"On Her Majesy's Secret Secret" has a bald Blofeld
"Diamond's Are Forever" has a full-head of hair Blofeld
"Never Say Never Again" (despite not an official Bond film) has a full-head of hair Blofeld
"For Your Eyes Only" has a bald Blofeld
They are just played by different actors.
There was once a rumor where there was one Blofeld with an army of clones to discourage the enemy to attacking the clones instead of the real Blofeld (Diamonds Are Forever), but that idea never paned out. The idea still has merit though. But they concluded Blofeld's reign in "For Your Eyes Only" when Bond threw Blofeld down a chimney.