Hi,
my name is Paulo Estrela an I'm a newly registered member. I saw your post on ID of a decorated British Officer of Peninsular War.
I believe, according with my (official) data, that there was just one british man who received both: Portuguese Peninsular War Decoration Cross, silver, for 3 years and the Portuguese Distinguished Command Medal for 1 action: Salamanca.
His name was Peter Adamson. Others who received Salamanca Medal were awarded with others crosses: Henry Watson (gold, 4 years), Charles William Crookshank (silver, 2 years) and John Richard Ward received Salamanca medal but did not received the Portuguese cross.
Anyway, are you sure that the pair belonged to a british officer ? And if correct (Peter Adamson), let me remind you that he was also awarded with the british Army Gold Medal (for Salamanca)...
I hope this information was helpful.