Thanks for the reply. On the outbound the entire J cabin is available - no seats sold yet. On the return there are a handful seats already booked. I guess the risk is if the upgrade doesnt clear ill be stuck with the Y seat that I have booked, and if i have booked the cheapest fare bucket, ill have to factor in adding baggage and choose seat options. Neither of the flights have any reward availability in J, per Avios and Ba website.