If the letters in 'toper' are removed from 'Reportedly', the result is REDLY. As you say, it must be correct.
I have one letter outstanding - the final letter in 17d (Change such as Pierre named after one without regular income). It looks like EDIT (as in Change) but what is the wordplay? 'DI' could be 'discretionary income', mais qui est Pierre ?
I couldn't imagine attempting the Mephisto after too much vin rouge !!