Thanks for the replies. I wanted to either redeem using avios or upgrade a paid ticket but I wasn't clear on my what my options were due to the mixed airlines. In the end I opted to do the outbound in economy and the return in J on a BA operated flight as I'd rather not take the risk of not being able to do an airport upgrade. I got 64A on the return so I should get a decent amount of sleep which was my main priority.

Thanks

Bob