Hello Simon, for the dead crew, using Volksbund and the death cards on fold3 should give you far more birth dates.
You have also the link below that gives you the list of German buried in Cannock Chase War Cemetery, where most German who died in UK in WWII are buried:
https://fr.findagrave.com/cemetery/2...search#srp-top. Almost all the WWII entries have a date of birth.