Surely a 'Trial Lesson' doesn't have to restrict itself to exercise 3.
Depending on the time the student's booked, I'll let them taxi, then in the air they can have a go at basic effects of controls, try a bit of S&L flight, climb a bit descend a bit, sort of turn, and even try to work out where we are. That's half the syllabus touched on. If they're up for it, I'll demonstrate a stall and maybe a steep turn. I'll nearly always demonstrate a PFL (at least establishing the glide, field selection and initial positioning). So that's a good chunk of the rest of the syllabus all in an hour.
Oh, and if they live reasonably close we'll have a look for their house. If not we'll have a look at a cloud or the top of the haze layer if its in reach, or I'll position to get the sun reflected off a lake or point out birds flying below us or fly along the motorway and let them watch our shadow overtaking the cars.
OK that'll only go in the book as 1-3, but Trial Lesson Student has experienced flying, not just being a passenger.
My return rate is a good bit higher than 5%.
Madam Breakneck