I just received a reply from BA. So far, surprisingly good! They acknowledged I inquired about two vouchers and responded about one of them, the 75-pound voucher for not having a working IFE.
Quick background - the flight was business class from LHR to LA as part of a round trip from Hawaii to LHR. I planned to sleep so wasn't concerned about the lack of IFE but the flight attendant said it was a matter of principle and would put in a claim for me. Definitely good service!
Anyway, BA has increased the value of the voucher to 97-pounds and extended it to the beginning of December 2021, and acknowledged that the pandemic had made using the voucher virtually impossible to use. I thought I had a good chance of extending the voucher but didn't expect them to increase its amount. I was pleasantly surprised. I still don't know if I'll be able to use it, but I can't fault BA, this was a nice surprise. No news on the 200-pound voucher at this point.