I think this is very interesting. Neither I nor my wife (also GGL) nor our kids (Gold) have received the offer but both of my Silver partner card holders have. It seems to have a very wide booking time-frame and applies to LH CW flights. My wife just booked a C/J fare bucket trip in CW to DXB (no Saturday night stay) for about £ 7k, so clearly not the target market. BA certainly have sent out these targeted offers before but I don't think I have ever seen or heard of a full 15% off long haul Club with so few restrictions. I am not sure if it could be used with a BAH booking.

Something tells me all is not well at Waterside towers...