Slitherine

Two questions about artillery and FF

Can heavy artillery defending FF wheel ?

In page 129 it says that “the front edge of FF is treated as the front edge of a battle group defending them including for measuring shooting ranges” so artillery that is in contact with two FF bases (front and side) can fire from any of them?

heavy arty can wheel, but would no longer be defending FF.
Arty defending FF can only shoot in the direction it is facing. but the front edge of the FF counts as the firing base's front edge for measuring shooting ranges.
Just because a side edge is in contact with FF does not permit the arty to fire to its side.