I just phoned the Autosport office at Haymarket publishing & spoke to a very helpful lass.

The guide will be out next week, the decision to do this was taken for two reasons:

1) People tend to travel out later these days.
2) It will allow them to include more info from the test day.

To the first I say: My arse they do!
To the second: Fair point.  The ACO have made the test day pretty damn close to the event this year.  It was similarly close last year & the supplement had no detail from the test day and was pretty inaccurate in a lot of respects.  Seemed to me like it had been printed a good month in advance.  So imho fair play to Haymarket if they are trying to improve. 

We shall see.

Which brings me neatly to that last nugget of info:  There are 'significant extra shipments to France' arranged.  Usually available at the Radio Le Mans shop.

See you there
Tinweevil