Spotted these 'bell flowers' on a single stem in my local not over-tended cemetery (Hooray) which allows for surprising nature to have a chance to take up residence. From a distance thought they were Hair Bells. On closer inspection thought a Gentian. Back home couldn't see it in my wild flower books or any online listing.
Certainly looks like the ref you have supplied although indicating a darker blue in your picture ref from what I saw which may be down to 'digital thingamebobbing'. Description, also, of several flowers on a single stem matches what I observed.
Your most welcome the only way I have tried to ID it, was I have few in my garden which I bought as Bulbs years ago and a dead ringer for your photo I just lookup my trusty 1984 The Flower Expert Dr D G Hessaayon There must be many commercial hybrids mine are not in flower yet dispite being wll south of you