Sea assault from two sea spaces

Situation.  
Danish Sea - British BS x2, Dest x1 and TRNS x2 carrying full load.
Channel - TRNS x1 carrying full load with Dest x1.  These could not reach the main fleet in the DSea.

No enemy present in either sea space.

Both fleets launched all troops in an anphibious attack on Netherlands, defended by 4 German Inf.

Arguement - German
Given the assault was being launched from two locations Naval bombardment needed to be determined for one fleet say the DSea fleet, first followed by the land battle BEFORE rolling Naval Bombardment for the Channel Assault.

Arguement - British
The source of the assault is not the factor under consideration here, both fleets have access to the destination (Netherlands) and both fleets have Bombardment vessels accompanying the landing troops, TRNS.  Which is how the rule book defines a valid bombardment.

Believed conclusion
If the Germany view was right then any time two sectors attacked one you would need to handle the battle as two or more isolated battles.  That is not the case so this would be one battle also.

We ended up playing British way.  Which is correct.