Dead Ball Penalty

[Chess Ref]

Standard high school set up in our area. Temporary fences that stretch from foul line to foul line. There is a gap from foul line to dead ball line, usually a chalked line.

Any balls that go beyond fence in foul territory are ruled 2 base award (ground rule double).

Batter hits one over F5's head, lands, and starts tailing into foul territory. F7 runs over, knocks the ball down, and as she is reaching for the ball, kicks it past the temporary fence.

I ruled 2 bases from time of pitch. Offensive coach stated she should get an extra base.

I'm thinking 8-4-3h is the applicable rule ?

Thoughts ?