Well, that was the date it was announced on the front page of OED's
in-house newsletter (The Periodical).
Official publication day was 19 April.
---
In June of that year, a celebratory dinner was held Goldsmiths' Hall,
London. (It was broadcast live by the BBC.) The Prime Minister spoke to
150 diners, including the co-editors Craigie and Onions, and assorted
other dictionary people, academics (J.R.R.Tolkien and Franz Boas were
there) and the like. All men.
Three women were present, by invitation, (one reader and two editorial assistants), but seated in the balcony -- house rules, apparently.

"Agnes Carswell Fries, who was invited because her husband Charles* was
editor of the _Early Modern English Dictionary_, was having none of it.
'I was told that the women would be "skied" if they wished to come. It
was explained to me that being "skied" meant that women could sit in the balcony above the hall and watch the men eat. I felt insulted and
refused to go under those circumstances.'"

*Yes, this is the same Charles Carpenter Fries (1887-1967), who is
better known to me as a mid-century American structuralist and innovator
in language-t

Ar an cúigiú lá déag de mí Feabhra, scríobh Ross Clark:

[...] In June of [1928], a celebratory dinner was held Goldsmiths' Hall, London. (It was broadcast live by the BBC.) The Prime Minister spoke to 150 diners, including the co-editors Craigie and Onions, and assorted other dictionary people, academics (J.R.R.Tolkien and Franz Boas were there) and the like.

Ignoring the androcentric aspect of the gathering, isn’t that amazing? That the
completion of a *dictionary* would be *broadcast live* by the national broadcaster, and that the PM of one of the more powerful countries in the world would address the dinner? Unlikely to happen now!

--
‘As I sat looking up at the Guinness ad, I could never figure out /
How your man stayed up on the surfboard after fourteen pints of stout’
(C. Moore)

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