Dear Steven
Thank you I think I now understand the error made.

Boppe (1899) wrote a book. He identified the Regiments as 2nd Barcelona Cacadores. This was then copied by Knotel, Bueno etc... It actually meant the second battalion of light infantry not the 2nd Barcelona Cacadores.

Estado (1821) clearly shows the 1st. This was taken by Arteche (c1860) and Oman (c1899) the the English language.

Does that seem a reasonable explanation.

Comments welcome.
Stephen