It depends on the details, as ever, but my guess is that Mennens on WTP to WT won't be a lot of money, given that it seems to be just the return leg. If CZ offers a premium economy product on the service in question then that should be booked but I think only a few CZ aircraft offer PE. Going via QR and DOH may allow WTP from DOH to London on BA. So yes, WTP travellers may well lose out on this, and PKX is 650 miles form PVG so rebooking from there won't usually be allowed either. Refund is still an option, but that also requires the TA to play ball.