If you hit something whilst being marshalled, it is still the captain's responsibility.
In my view, this is one of those situations where no-one is right or wrong. The fixed wing was cleared to taxi, as was the heli. Whether the heli is in flight, isn't really relevant. How else does something like an R22 manoeuver on the apron under its own power?
To be honest, only one controller should have been in charge, rather than ground and tower. This could lead to loss of situational awareness, especially if they are seperate frequencies and neither traffic is aware of eachother.