As is often the case with the Office of Fair Trading, its advice depends upon how you phrase the question and who’s providing the answer; contact them and ask the question again in the same way and I’ll bet you get a different interpretation.
As advised before, it’s the person or entity who wants their interest recorded on the Strata Roll that’s responsible for providing the S118 Notice, and in the case of the sale and transfer of title for a Lot that’s customarily the role of the Solicitor / Conveyancer acting for the (new) Owner.
As Secretary, you can request a S118 Notice from a person who you believe should provide one (and hasn’t), but beyond that you can only report what’s shown in your Plan’s Strata Roll, and if that’s incorrect or incomplete then let those acting for the Vendor and the Purchaser sort it out!