EGPWS
Dear Sir / Madam,
I think you might be over complicating the issue slightly.
The regulations outline the requirement for standard equipment, not "minimums required for a Maintenance deviation despatch". Your instance is relative to MEL item only. In this respect it is "and / or".
I understand this to be an "A" item. You are allowed to despatch for 24 hours with either Both parts of the same system out or just GPWS operational. Lets face it you wont get just the "E" part working on its own.
I hope this answers your question.
Best regards, and happy holidays.