While surrender is always an option, you do have alternatives here. Even if you do not want to pursue arbitration (which is probably not as complicated as you seem to think), the consumer arbitration rules to which BA agreed preserve your right to sue in small claims court. Unless BA were to settle, they would be forced to explain the basis of their actions in either court or an arbitration hearing. If you're not willing to sue or file for arbitration, it seems to me that you have little to lose by going to the media. Regardless of whether BA or your travel agent is in the wrong here, you should not be made to suffer.

It occurs to me that if each of the ~ 25 affected clients were to pony up the $200 arbitration filing fee, BA would potentially be on the hook for ~ $100,000 in arbitration fees alone, to say nothing of the attendant attorney fees. I think that that would get BA's attention pretty quickly!

In terms of being worried about being "banned for life by BA," I suspect that the poster who brought that up was talking about being banned from participating in BAEC, not about being banned from flying on BA (although I suppose that either is possible). I note that some years ago, several members of AA's AAdvantage program were banned from that program after AA came to believe that they had engaged in some shenanigans in applying for AA credit cards. But they were not banned from flying on AA: they could still buy cash tickets on AA and credit the flights to BAEC or some other oneworld program; and they could still redeem miles from other FFPs for award travel on AA.

You might want to discuss your options with a competent California attorney before making a final decision. Losing 295,000 Avios is certainly not the end of the world, but it's not nothing, either.