Here is the section on the EB91 from Philips Technical Library Book IIIC, “Data and Circuits of Television Receiving Valves”. The English edition was published in 1953, although the book appears to have been based upon the (predominantly noval) range of TV valves introduced in 1950. Anyway, it is apparent that at that time, the EB91 was Philips’ preferred double diode type.
EB91 Philips Book IIIC 1953.pdf
The EB41 had been covered in Book IIIA, “Data and Circuits of Radio Receiver and Amplifying Valves; (Second supplement; Valves developed during the period 1949/50”. The English edition was published in 1952.
EB41 Philips Book IIIA 1952.pdf
As may be seen, the EB41 was also said to be suitable for FM and TV applications.
The Philips preferred double diode progression was thus:
EB41 (from c.1946)
EB91 (from 1950)
EAA91 (from 1954, if not earlier).
Mullard apparently stayed with the EB91, not moving on to the EAA91.
Cheers,