Hey Horatio, stop bagging out my flying school
1/. Students were not taught to lean the mixture until after they passed their PPL;
This was pretty much the case for me. Rarely did a flight go over 2,000 - 3,000 ft so it was never raised until very late in the piece, in fact it may have been during a pre-licence test NAV. The explanation given wasn't fantastic either. The instructor hadn't been to Jabba's school of engine management.
4/. no flight plans or SARTIMES were ever lodged "because there was always someone at the school to hold company SAR".
This has also been the case at every school that I have ever been to other than for PPL flight test and AFR's. In fact from memory I did submit flight plans but have never submitted a SAR time to the authorities throughout my dealings with any flying school, ever. Due to your point number 4.