Why, by the way, did you opt to use the 2nd argument in the WEEKDAY
function call instead of the simpler single-argument form of this
function?

Because the OP has a UK e-mail address, and I'm not sure anyone
outside the US thinks of Sunday as the 1st day of the week. That is, I
was guessing the OP would find it more obvious to think of Thursday as
the 4th day of the week.

Ah! That is interesting. Not having an international background myself, it
never occurred to me that other countries might start their calendar week
with Monday instead of Sunday. That would probably be the explanation, then,
between the Sunday/Monday start of week options on those date functions
offering a start-of-week option... I just figured the option was there for
company workweek usage only, not for general calendar use. You learn
something new every day. Thanks Harlan.

Rick