I'm not an expert on these cars but since nobody else responded, here are some hints:
Angela Cherrett was mentioned in this thread. I hope this answers the question about experts.
With respect to a restorer in Europe, Fabio Caligaris in Italy may be your man. I've seen a 6C 1750 in his excellent restoration shop near Milan when I visited him 3 years ago. He is the technical advisor for the 6c2500 register (see http://www.6c2500.org for contact information) and is a very nice guy who speaks English.
Angela Cherrett was mentioned in this thread. I hope this answers the question about experts.
With respect to a restorer in Europe, Fabio Caligaris in Italy may be your man. I've seen a 6C 1750 in his excellent restoration shop near Milan when I visited him 3 years ago. He is the technical advisor for the 6c2500 register (see http://www.6c2500.org for contact information) and is a very nice guy who speaks English.