I am trying to book flights for my wife and I to Tokyo next year to celebrate a very, very big birthday and our wedding anniversary. I can get flights back at the end of April but even with Didsbury's help I can't get flights outbound. Despite many completely empty flights there are no D class seats available for a month or so from mid-March to mid-April, something confirmed by Expertflyer which only shows JWYBH booking classes. Didsbury says that this appears to be "for commercial reasons" that they can't override. Does anyone know why this might happen and/or what these commercial reasons may be?