Also, FWIW not all yeast from the province of Champagne is ideal for sparkling wine production. Red Star's Pasteur Champagne, for instance, is just a wine yeast from Champagne, but is not a sparkling wine yeast. There is also a distinction between "sparkling wine base" yeast and "secondary fermentation" yeast. EC-1118 or Premier Cuvee are the best for "secondary fermentation" (bottle conditioning). It is a fast, neutral fermenter with low nutritional requirements.
AFAIK EC 1118 and Premier Cuvee are the same, or at least very similar strains.