On this map for B&B accommodation, results C, D, E, H and J appear to be coded into the map and have a “bed” icon, whereas the other results do not. Can anybody explain why?
I think it must be on what you have used to describe your business in either Google places or webmaster tools.
One of my sites is Beauty salon and that is a boring red circle with a white square and I think this must indicate there is not a suitable icon to use. All the other beauty salon results have the same icon so I assume it is a default one.
Car sales comes up with a red circle with a shopping bag.
I don’t think that can be it. Every one of them is listed as “bed and breakfast”. C also has “campsite” and D also has “guesthouse”, but the others simply say “bed and breakfast”. Nor would that explain why some of them are marked on the map itself and others only appear as flags.
It looks like it’s something that whoever codes up the map needs to do
It looks like it’s something that whoever codes up the map needs to do
These icons are for maps on your own website, the icons TechnoBear is talking about are on the Google maps straight from Google.
If you open google maps and search for something like car sales some of the business have custom icons. I still think it is something to do with the way Google+ or Google places is setup.
That’s not what I was talking about, but that looks useful for other purposes, thank you. 
I’ve now discovered that if you zoom in as far as possible, all of them have the bed icon, apart from B, which has a dot. 
Why only some of them show at a more normal zoom level is still a mystery. But then, Google maps as a whole are pretty much a mystery to me. I never did find an answer to my previous question about how to get a description to show - and it still doesn’t. 
Anyway, it looks as if there’s nothing I can do here to get my client’s “bed” icon to show at less than full zoom, so I’ll stop worrying about it.