Yeah, the whole battlegroup tried and failed, but then a wing of Boanerges class bombers and a Sobek took it out
The Lysander was SEXPed to death, I've taken out the Ravana's beam cannons before it fired a shot and the Lysander STILL died
. The Hercs could disable the Ravana, and destroy the (weak) shivan fighters, any that survived could be destroyed by the Deimos's heavy anti-fighter weaponry.
Granted the forward firepower of the Ravana could quickly vaporize a corvette, but their manuverability would allow them to stay out of the Ravana class's narrow FOF while the huge FOF on the Deimos allows them to fire sideways at the Ravana while it avoids the main beams.