Ian, I don't know if you have this Osprey book, but it might come handy.
OTTO VON PIVKA - THE PORTUGUESE ARMY OF THE NAPOLEONIC WARS
A very decent concise summary of the Portuguese forces, uniforms, etc, especially considering that it is in English.
It's available for preview here -
http://books.google.com/books?id=FdL...age&q=&f=false