Certainly not the best chart ever produced and I would agree with BOAC's interpretation and it looks like the B767should not have been "passing 1600' at 8.5D.
And I would respectfully point out that as this is a circling approach, it is not meant to be "doable" from either 6.5D or 4.5D i.e. a landing. Surely on reaching MDA by 4.5D AND visual, one should proceed to circle over the airfield to land. If not visual by 4.5D then of course follow MAP.
Having said that it is a circling procedure, nothing precludes the pilot from making a straight in approach to land if he is visual early on in the procedure, in fact it is expected by ATC (in general) that he would do so.
What I think is quite wrong is the dotted line from 4.5D to the threshold almost inviting a final approach to land from that position which would be very steep (though from 6.5D it looks manageable even if not required)