Ambiguous comment of mine there. I meant "now that I have got silver on S15 . . ."
Anyway, last weekend I found time to pass this challenge honestly. While trying, I suddenly realized that perhaps I was failing because I was trying to pass the other cars in the chicanes.
And so, given that you draft pass the first car before the first chicane (passing on the right seemed to help me be ready for the imminent chicane), I decided to merely use the chicanes to close up on the next car, so that I could pass it on the subsequent straight.
After a few tries, I got that to work.
Pass first car naturally by drafting.
Close up to second car in first chicane, and draft by it on the following straight.
Close up to third (i.e. first-place) car in second chicane, and pass it going into the Mulsanne Hairpin. I think I forced the other car wide a little, but I finished first by a clear margin with no lawn-mowing, no 5-second penalties, and no excessively undue forceful contact.
The same weekend I also redid
Mission 6 cleanly. (which see)
So now I own my Delorean honestly.