Thanks W2G, that helps. What I'd thought might be a picnic table is actually a "motorway" symbol then!
So when it comes to ticking which POIs to show on the map, I DON'T tick the actual "Aires" one, just the specific types I'm interested in from among all the others.
The categories make sense to me because I understand some of the distinctions the French make between different places, but since this is a "sticky-thread," may I spell them out for the benefit of others (and to make sure I've got them right)?
ASV.ov2 - Areas of Verified Services - are places where water can be filled/emptied (including toilet).
APV.ov2 - Areas of Verified parking Lot (or stationnement) - are places where a car (and therefore a motorhome - ALWAYS) can park overnight.
AAV.ov2 - Areas on Verified Expressways - are motorway service areas which offer water facilties. I'd doubt the wisdom of staying there overnight but it's probably legal.
ACV.ov2 - Areas on Verified Camping - will be places where you can not only "park" overnight, as above, but actually "camp," even if it's not a formal campsite. The difference in French law, as has been said elsewhere on the forum, is that a motorhome is "parking" if the only thing touching the ground is its wheels. In that case, if a car can park legally, so can a motorhome - EVEN IF THERE'S A SIGN SAYING OTHERWISE (although I'm not sure I'd want to argue that case with a Gendarme in the middle of the night!). However, as soon as you put anything else on the ground, even corner steadies, you're "camping," which may be prohibited even where parking is allowed.
As for the "not verified" sections of each category, I don't think I'll tick them. The last thing I need for domestic harmony is to arrive at a place late in the evening to find we can't stop there after all!
Thanks again W2G, and if anyone wants to correct or clarify my contribution here, please do.
Tony