Neville asked Aldous Huxley whether anyone listing the six greatest users of the English language could omit Blake, and Huxley answered that he had just said the same thing.
Date (happened)
between 1951 and 1952
unresolved
between 1951 and 1952
estimated · probable · preferred
Reasoning
Counting five to six years back from the lecture's own well-corroborated delivery date of 1957-09-15 (calendar cross-check of a Sunday-15-September departure statement against the Blake bicentennial line) places the Huxley conversation circa 1951-1952. A range rather than a point date because 'about five or six years' is itself an approximation; confidence capped at probable, the ceiling set by the delivery claim it rests on.
about five or six years ago
relative
between 1951 and 1952
bound · possible
Reasoning
Neville gives a rough relative offset ('about five or six years ago') from this lecture's own stated/exact but only probable 1957-09-15 delivery date, giving an approximate 1951-1952 window.
Told / reported
15 September 1957
estimated · probable
Reasoning
Neville tells the Huxley anecdote from the platform, so field_told equals the lecture's delivery date. No field_told claim previously existed for this event.
15 September 1957
stated · probable
Reasoning
The lecture whose passage (556845) recounts this conversation is dated 1957-09-15 by a stated/exact but probable delivery claim (Sunday/15-September plus Blake-bicentennial cross-check); told confidence is capped at the lecture's own.