the last one was about was about 20 years ago . but with amount of field goals attempted now .it wont be long before we see another

are you Stevo ?

I never knew this existed until it was mentioned in the Broncos Cowboys game. I knew about the 8 point try, saw one a few years back in SL but knew nothing of the 3 point field goal.

Is this basically a penalty for foul play on a player during/after the drop goal has been taken? And if so, is it taken where the foul was? Or 10m from in front of the sticks?

If it misses - it's where it bounces/is next played.

If it goes over - 10m out in front of posts.

if it misses, surely its just a standard penalty (i.e. 2 points).

If it misses it's a penalty where the ball bounces if it bounces in the in goal it's from in line from where it bounced ten metres from line and it's just a penalty with the option to tap, kick to touch or go for goal (worth two points). If the drop goal is successful the drop goal is awarded (one point) and a penalty is awarded where you must go for goal worth another two.

Yes, an optional kick, so could just tap it for example. If the DG was successful, a resultant penalty must be taken at goal.

and if the penalty kick for goal .is missed but stays in play . what next ??

Game is already "dead" - kick-off from half way as normal.