I'm just preparing a CEDR application form for a claim that's now 10 weeks old and I see that CEDR have updated their adjudication rules in respect of application forms received after 1 May 2022. I've not gone through them word by word, but see they've changed various references to EC Regulation 261/2004 to the replacement Air Passenger Rights Regulations. Most significantly, though, they have added a new rule 4.1.8: "In exceptional circumstances, and with the approval of the Civil Aviation Authority, CEDR will have the discretion to vary the timescale at Rule 4.1.5 above."
4.1.5 is the rule that gives the subscribing party 15 working days to respond. So, their previously informal practice of giving BA extra time to build their defence is now formalised and, it would appear, the CAA has approved of the practice.