You need A class availability in First and I class availability in Club... shouldnt be too difficult to find. Max stay is 30 days- maybe thats it?

No stopovers permitted, but thats all about definition- a stopover is anything over 24hrs, so you can be creative and still have a night in London on these fares (i.e. arrive in London 7pm and so long as you depart next day before 6.59pm its not a stopover...)

If you post the dates and routes your looking I'll see if I can get the good fares...