I was also taught - and used to teach - turnbacks when I flew the Bulldog.
It was an option of last resort, as far as I was concerned, and I would always plan other avenues if they were feasible.
Reaction for the turnback had to be instant and instinctive. Immediate selection of the correct descending steep turn attitude was essential - and the objective was to land on a flat part of the aerodrome, not necessarily the runway. Which could, of course, be occupied..... You had to be above the key height to start a turnback, otherwise it would kill you.
I gave a relatively good student a simulated EFATO at about 200 ft agl once and he started a turnback....for all of 0.25 sec before I took control and re-applied power. We'd recently changed to QNH take-offs and he'd forgotten the elevation, so was lower than he thought. If you need to have instinctive height keys, QNH can kill far more easily than QFE.
On the Hawk I was also taught turnbacks. Because it had such an excellent wing, you would utilise excess energy by turning hard one way, before reversing into a gliding turn on the buffet nibble. It worked fine, but needed practice.
Whereas on the Gnat and Hunter, we had no such option. It was invariably a bang out situation if the engine failed after take-off.