I quote from my RAF CFS lesson plan (for the Bulldog, just dug it out from under it's dusty cover):
TURNBACK
Lower nose to 80 kt attitude
Smooth and positive 45 degrees AOB
Level wings on reciprocal
Flap A/R
Min height 350' agl
I have practiced from 350' (we didn't practice the landing, we only ever went around from a low position to avoid the risk of aircraft damage) and I certainly wouldn't want to attempt it any lower. By that I mean physically and positively beginning the manoeuvre, not thinking about it, or having a look. There were some practices where I said to myself "that would have hurt for real".
I would stress that the RAF taught the turnback as a last-ditch technique for where there is no alternative forced landing area upwind or crosswind and it's certainly not for the indecisive or ham fisted. Someone mentioned flying on the buffet. I wouldn't do that, a flick from 45 degrees AOB close to the ground would be irrecoverable. The 80 kts mandated for the Bulldog kept us just out of the buffet.
Once the surface wind picks up, the more likely I would be to discount the turnback option altogether.
I would advise anyone not taught turnbacks, or not in current practice on the aircraft type in question
not to attempt it. Sometimes it might be better just to depart from an alternative runway in the first place, if there is a choice. Although you might land on the airfield near the fire engine, it could well be a hard, fast landing and possibly not on the runway. After all, who deliberately and regularly practices downwind approaches and /or landings?