This cultivar of Melittis melissophyllum is called 'Royal Velvet Distinction'. In the wild it is a woodland species (known colloquially as Bastard Balm!). The label says Royal Velvet has PBR i.e. Plant Breeders' Rights which is in effect a form of copyright.

 The website of the Canadian Food Inspection Agency has a section devoted to PBR with an interesting description of the propagation process:   

 "Origin and & Breeding history: 'Royal Velvet Distinction' was selected in Oudelande, The Netherlands in 1996 from a seed bed of hybrid Melittis melissophylum seedlings that were produced from a cross of two unidentified Melittis melissophylum selections. It was selected on the basis of unique floral characteristics and plant habit".

 I saw these two healthy looking specimens on a market stall for £7.95 each. I don't want to be a man who knows the price of everything and the value of nothing but the cost of plants from garden centres, mail order etc. seems to have gone up very steeply in recent years. Pots of this size that were commonly £8-10 a few years ago are more like £13-15 now.

 I prefer to propagate my own but where good plants are good value I'm happy to take a short cut and buy them.