Ohhhhh...La Plagne is definitely a no-go then.
Yeah, the French law is pretty crap for the British tour operators in resort now. However staying in a chalet you'll more likely to find like-minded people and groups who won't mind someone else tagging along for the day.
Neilson Active Holidays normally offer a packages for solo travellers.
http://www.neilson.co.uk/ski/solo-ski-holidays
The chalet option in La Plagne looks decent.