I am sure the breeder did not "lie" to you, but perhaps obtained his birds (from breeder in England/Wales/Scotland) and they were not properly labeled for him. Variety names are easily misunderstood, especially,if Dutch is a new breed to him. If from a Sales Site, "anything goes". If from a recognized Breeder, no one wants their reputation questioned, by a wrong, not predictable, variety from a sale. Perhaps you will find a Poultry book with pictures of breeds, Large Fowl and Bantams, and it will have pictures of the Columbian variety, that is recognized in many breeds, such as the Belgian Bearded d'Anvers, Light Brahmas, Cochin, Cornish, Old English, Wyandottes--others--all the same Columbian color/pattern description. Likewise, there will be pictures like your pullet (cockerel is not shown as a pattern well defined in his picture) as , Barred,or Mottled. In the US Standards description, Barred has variations, such as in Dutch Bantams,it is called Cuckoo, and variation, as in Crele. I am certain that the seller of your birds, has no intention of misrepresenting the color/variety, but is confused or has not researched the Dutch variety descriptions--or birds were mislabeled when he obtained his breeding birds. He has listed a lot of varieties--(and so many other fowl!)--sounds like a Hatchery! Could you properly pen, and keep breeding records of the chicks hatched, with 10 varieties of just one breed. Almost impossible to keep them separated or sorted properly for breeding the varieties. Or does he just purchase and import, eggs. Then it is just a guess whether the chicks will be as the eggs are labeled. Almost impossible, also, to identify some varieties by down color, at hatch And he lists most varieties ,that are few in numbers--anyplace (such as the Columbian, Blue, Crele, Mille Fleur, Lemon Mille Fleur, (in Holland, these 2 varieties are called Porselein and Citroen Porselein), Lavender, Black, White). And he misnames the varieties that are best known in Dutch worldwide: Gold Partridge, Yellow Gold Partridge, Silver Partridge. The Columbian, in Dutch, is a very newly recognized variety in Britain and also, in Holland, developed over quite a time, in England, by the former Secretary of the Dutch Bantam Club, UK, not at all easy to locate in Britain..
I kid you NOT, your Dutch are NOT Columbian variety. They are a Barred variety--Cuckoo. And genetically, the Cuckoo CAN NOT have blue legs--and even the crosses of Cuckoo with other varieties, also are very difficult to breed with Blue legs! This includes my Mille Fleur and Cream Mille Fleur. (Citroen MF) Dutch--after created in Holland in 1990, still getting light legs in many offspring..This should be a major clue that your birds are of a Barred variety, and NOT Columbians.
Be optimistic that your birds are DUTCH and that the variety can be properly named, so that you will have a good and pleasurable breeding project!
(looking for Cuckoo Dutch pictures--may take a while). Personally, I would not purchase birds from a person who could not not show better knowledge of the birds he is selling. With the Dutch just getting a good start in Ireland, keeping them predictable and with good records of breeding pens, will ensure their good demand==Dutch are such lovely little bantams!
Best wishes and Good luck
Although my heritage is partly Irish, sadly, and I have tramped all over Britain from N to S, I have been unable to visit that beautiful land!!