Ltd, Hong Kong
, launched their Grand Banks
line of powerboats in 1962.
Previously, they were running a “custom” boatyard; hence the “Lotus” may have been a “one-off”, rather than a class or line.
Accordingly, such a boat would have to be “valued” in comparison to equivalent boats. Should you, like I, be unable to provide an expert comparision to boats of similar construction, condition, and age; then you, like I, would be unqualified to provide a “range of value”, and would properly survey
the vessel for condition (what works & what doesn’t) and suitability for purpose (and PERHAPS an estimate of cost to refit
Don't overstep your expertise.