Ah, just as well I went this year, to Thenay.
I must say that it was a fantastic experience.
From Australia, it was a once in a lifetime serendipity that coincided with a visit to France,Spain and Portugal.
We met a few people on this forum and shared the love.
Sorry Simon, I can't help you there, but vehicules-anciens.fr have quite a following on social media, and as 4L International isn't until 2019, I would guess this event in the south would be well attended. It coincides with the Tour de France being in the area that weekend, so as far as I'm concerned that's another good reason to head in that direction.