The navy dress is very stylish and elegant, from an Australian designer. More details about this final event and the dress are here, with a view of the back of the outfit (scroll down):
It appears much better fitted around Meghan's waist and bust areas than a couple of her other outfits in recent days. And it's her trusty monochrome navy palette.
The same designer made the burgundy wrap top that Meghan wore in Australia during the Invictus Games.
Regarding the unusually styled light rust-colored dress Meghan wore for the QCT event at BP, I had to laugh at this cheeky Twitter comment:
"Her outfit* is matching Harry's ginger. Make them stop!"
Another apt comment on Twitter exclaimed that Meghan gave us the four elements in fine style during these final engagements:
(resplendent bright green for Commonwealth service)
(sheer white on Jacquard white for the National Theater visit)
(fiery red from head-to-toe at the Royal Albert Hall concert)
(stardust magic turquoise for the Endeavour Fund Awards)