...I'd like to have some idea of his credentials.
Ken's contact info is quite easy to find. Click on "contact", located at the top right-hand corner of the site and it will bring you to
this page. His phone number, mailing address, and e-mail are there for all to see. Ask him about his credentials.
But as you say, this is legal English and very formal. Some dictionaries may recognize 'timely' as an adverb, but I've never heard or seen it used that way - except in very formal and archaic contexts. I agree that the best thing is to rewrite the text, but I'm sure it's possible to do it without making it sound as if it was written by Dickens ;-)
I wouldn't go so far as to describe legal English as "very formal". If anything, it's too wordy (ambiguity intended), and the reason Ken advises using concise "timely" instead of verbose "on a timely basis"--the blurb is about 'verbosity in adverbial constructions', right?
True, some dictionaries recognize "timely" as an adverb, and they are USA based. I, too, have never heard "timely" used that way. I came across a few examples while searching on-line, all
legal English examples, some with added explanations that as an adverb it's rare, and that it's considered archaic in BrE, just as you and Ken have said--you both seem to agree there. On that point, does one really require credentials to make the observations that you and Ken have made?
In sum, rephrasing is the way to go, as you and Ken have suggested (Oh, gee, look at that, you both agree again).
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We'll talk about "weasel word" when I get home... :lol: