I just finished revising and playtesting the Battle of Portland scenario for use in Privateers Bounty. I created three groups that were close to the Dutch, with William Penn in a group of 12 ships the furthest west; Robert Blake with about a half-dozen ships east of that; and to the immediate southeast, John Lawson with about a dozen more ships. Further to the south was George Monck, with his squadron and the stragglers. I also switched out ships in Penn's group to reflect the ships that were known to be with him.
This makes for a much more accurate start to the battle, to have the English flag officers exposed, without their complete squadrons. In the real battle, the Dutch gave the English a great scare. Penn's group was hardest hit, having lost the Sampson (26 guns) sunk and three ships taken. The situation was sharply reversed, however, when Lawson's squadron arrived on the scene. He had previously fought off Jan Evertsen's squadron, inflicting heavy losses on them, and then recaptured the lost ships and drove off the Dutch, ending the battle for the day.