A bit more information you might be interested in
Earlier this year Juan Campos Calvo-Sotelo, attended the annual Shipwreck Conference at the University of Plymouth, see:
http://www.shipwreckconference.org/Mr Campos gave a talk on the loss of HMS Serpent. He has written a book on the maritime losses along the Gailcian coast:
"Náufragos de Antaño" by Juan Campos (translation of sub-title "The Great Shipwrecks on the Coast of Death").
This book, written in Spanish, is about 19th century shipwrecks on the Galician coast, mostly British.
Some of Juan Campos's information has been included in this website, and duly credited." [this was extracted from the following website:
http://www.hmscaptain.co.uk/default.html]
Mr Campos can be contacted on
juanserpent@yahoo.es and the publishers of the book (in 2002) were Editorial Juventud, Provença, 101-08029, Barcelona.
I think you should try emailing Mr Campos - he seems to have a particular interest in HMS Serpent.