Chase would not agree to a "final" redemption for BA miles. However, they credited 2,500 bonus points for the inconvenience -and- they agreed that the Amazon points could be transferred to Ultimate Rewards (which can be redeemed for BA miles) if we open a Sapphire Preferred account.
After a phone call followed by two secure messages I was given 2,500 extra points. At this point I wrote back and said in no uncertain terms that this was not acceptable, as I'd diverted significant additional send to my Amazon card just to get the BA miles that are still showing in their online brochure. A few days later I got a reply asking for my BAEC number and asking how many I wanted to transfer - as a one-time only deal. I replied and said transfer the lot (30K+). I'll wait and see how long this takes, and then take up a similar battle on behalf of Mrs User Name.
Crappy Chase customer service as usual turning the most simple and common sense thing into a long drawn-out battle.