Why a junction at Brest would still face British concentration

Napoleon claimed that Villeneuve should have collected the Spanish squadron and sailed to Brest, allowing the invasion of Britain to proceed. The counterargument is that British communications and fleet movements would have brought Calder and Nelson to reinforce Cornwallis. Roughly twenty-seven additional ships are envisaged alongside the force already outside Brest. In this scenario, the decisive confrontation changes location without giving the allies the easy opening Napoleon imagined. Cornwallis would also have been available to lead part of the British attack.