What is the cheapest revenue business class fare to LHR from Canada (in my case Ottawa) during the summer months of July and August, on a Star Alliance Carrier (AC?, UA?, LH?, Austrian Airlines?, SAS?)? What is the best routing (ie would it be cheaper to go via Paris on AC, and then connect onto British Midland?)? What is the best way to get such a fare (do C fare codes exist on this route?), and through which agency (the airline, or through a travel agency that specializes in discounted business class tickets to UK)?

I am asking this question because I do not feel that as an Elite member, I can successfully upgrade from a Y class fare, using my system-wide upgrades?