The car is a 100/6 Longbridge car, BN4L-O-59375 fellas
Thanks Derek, incredibly helpful and your website is a treat....bookmarked
I'm pretty sure I have the correct frame which came with the car ( I have 2 !! ) when I purchased it, but none of the clips / clamps affixed to the car as shown in the diagram, they seem to have been removed
I will need to get to a couple of Healey meet ups and study some other owners cars
L