No worries.
RA - Reactionary Delay (late inbound aircraft)
TC - Change of aircraft due Tech issues.

You need to wait 8 weeks from initial complaint/claim until you can proceed to CEDR. Having a deadlock letter can in some circumstances speed you that time Interval as BA have stated their position will not change (until forced to). By all means reply and ask that given the delay code allocation, timing as and notes for the BA2656 on the 8th, how on earth did BA expect to get the aircraft to ALC that late by ATC means alone? Hopefully common sense will prevail as the information I’ve provided is what they’d need to disclose in their operational legs report that is often the basis of their rebuttal, along with a length wiggle waffle letter that frankly should describe the chemical constitutions Kellogg Frosties as it generally has no basis in reality on what occurred to a particular flight and is merely provided to make you doubt the outcome, but I personally do find them interesting when they’ve been placed on the EC261 thread which is where this conversation should now continue so as to keep this thread free for delay and can’t listings and codes. They do make good writers of fiction on occasion.