Mike,
Breath? Not at all; the folks who
really know about these things will either be: dead, in a care home, Florida, Thailand, not into e-mail, or, like myself, permanently out to lunch.
Have you contacted Classic Team Lotus?
http://www.classicteamlotus.co.uk/default.aspxThey might be able to put you in touch with Bob Dance or someone who was there at the time but don't expect them to fall over themselves, why should they? Searches like yours often take months... or years.
You might need to change your attitude/expectations unless you are in a position to offer cash.