DjPil, thank you for your advice. According to "The Incomplete Guide to Wing Sections" it is indeed the same section and I have obviously been barking up the wrong tree regarding the drag build up. The approach speed demonstrated and practiced is on the fast side of the POH recommendation, but within the limits, and the drag increase as you close the throttle is very pronounced, at least to me, much more so than an Arrow.
You would know and I'm sure approve of the instructor involved, who has suggested that it would now be rewarding for me to concentrate on precision in my flying and that with heavier aircraft and a trusting friend or two on board, that a little finesse in the handling of the aircraft and powerplant would be a good thing, both for friends nerves and larger powerplants.
I take comfort from the constructive comments here, especially yours, Chimbu and Bushy. As a curious person, I like to know why I'm advised to do things a certain way and whats behind the POH and recommended procedures against the day I run into uncharted territory.
As for the others, critical of me for having the temerity to even raise what to me was an issue, I'd like to remind you that there is considerable and ongoing debate on Pprune and elsewhere about training standards, something that has even got CASA's attention. Your posts demonstrate that reform is long overdue.