Well done! When I want redemptions I look several times a day and frequently find one appearing. Not only do BA release seats but also other people cancel. Either way you can be lucky.

Unfortunately, the key to this is flexibility of travel dates, not having non-refundable hotels and not travelling on a companion voucher. The latter restricts your choice of airline when partners pop up. You need to be careful sometimes as, for example, BKK - AMN - LON whisks you in J on the first leg on RJ but if the second is on BA they use short haul aeroplanes with Y seating, avoid at all costs!