QUESTION: Whodunit?

A few days ago I received an email asking me whether I could possibly identify which engraver was responsible for this beauty here:


It is a die proof which was sold to the correspondent attributing it to Bradbury Wilkinson and Hong Kong. Which is strange as the Hong Kong definitive set utilising the Annigoni portrait is not engraved, nor recess-printed. My correspondent had already compared the proof to engraved Annigoni stamps from the British Commonwealth but found no obvious match.


Unfortunately I have not been able to find out anything, so that's why I'm posing the question here, hoping that maybe someone somewhere may recognise this item. Seeing that the size is definitely stamp-size (a mock up Hong Kong proof shown here shows that the engraving is of small-format definitive size), I think we may exclude any banknote usage.


Maybe, just maybe, it was a preliminary proof for a new Hong Kong definitive set after all? Only to be discarded in favour of cheaper and quicker printing methods? But that would have been slightly odd, seeing that as far as I remember no definitives from Hong Kong were ever recess-printed.

Anyway, any help would be hugely appreciated!

:-)
Adrian