I happened to check Diners Club Rewards while paying my bill and noticed they are running a 40% transfer bonus to British Airways Avios that ends today, 12/16/16.
Diners Club still transfers to British Airways 1:1, with minimum transfer of 1,000 points to 1,000 miles.
If you are one of us dwindling few with a Diners Club account, this is a strong redemption. I have not found any other transfer bonuses currently running.
Transfers are not instant. I don’t remember how long they take. You can pay a $35 expedite fee.
Warning: the Avios bonus appears to be limited to one transaction per account. After I transferred points, I went back to the account to get additional screenshots for this blog post and the offer was gone and did not reappear even when logging out and logging in. Since the offer is gone, I cannot access any terms that may provide explanatory detail.