Thanks for the quick replies.

Since both legs are confirmed for economy we have to confirm them soon - the MPC lady seemed to think we'd still stay on the waitlist for Biz even if ticket issued, and we would only be charged the extra 15,000 miles if they came through. Am unsure about this.

Our prev upgrades were on a paid economy at a fare that allowed a mileage upgrade.

I might hound them on occasional days for a month and see what comes of it. My boss gets his secretary to do that and seems to have about a 50-60% success rate from the sound of it.

Thanks!