I may be missing the point somewhere, but if I fly towards Wycombe ATZ, say, it pops up with the appropriate proximity warning but doesn't give me the tower frequency to request transit. That's not especally helpful - is it just that Wycombe frequency is missing or is it by design?

Some frequencies were missing from ATZ descriptions. We've updated them all now and you'll see this reflected in next Thursday's chart update. Thanks for bringing it to our attention.

There are still some zones (LFR93 in France) where the frequency is missing.

There is not always a frequency available to associated with a piece of airspace, and due to limited resources, we will not always be able to associate a frequency with restricted areas. Compared to controlled airspace and danger areas, it is much rarer to want to gain access to a restricted area (though France is somewhat different in this case).

Nowhere do we assert that we have frequency information for all pieces of airspace, or that our chart is a suitable replacement for a paper chart for all pilots.