The only "good collection of Anglos" you're going to find on that side of the pond is Barleycorn Concertinas in the UK. There are concertinas stocked and viewable online at Hobgoblin Music in the UK, but they are spread out in the company/'s individual shops around the country, don't know how well vetted they are, and don't believe they are restored.
There are also a couple of other folks in the UK who sometimes have one to three instruments, those being Theo Gibb at The Box Place and David Robertson, who restores and sells concertinas, you'd have to Google his name with "concertina" and his site should come up. They both are careful and reputable restorers.
In France, there is a restorer and dealer in the Montreuil suburb outside Paris central, named Laurent Jarry. His shop is called La Boite de l'Accordeon. He is principally an accordion guy, but also restores and sells concertinas, though not a wide array. His web link is below. On the left, click on "les occasions," to get the used inventory, and then scroll to the Anglos and click on that.
I see he currently has one 30-button, wood-ended Lachenal that might make a beginner instrument depending on condition. Don't know if that is brass-reeded or steel reeds in brass frames (I would prefer the latter, but some people don't mind brass-reeded for a learner instrument). Below that, there is a 20-button wood-ended Lachenal. There are schools of thought as to the advisability of getting a 20-button to learn on; I personally don't approve.
Edited by ceemonster, 31 January 2018 - 08:05 PM.