I am sorry but we see many people here having routings booked but tickets not being issued for weeks

Others may disagree but I am not clear that being rerouted means being ticketed and have your boarding pass.

you said

"The way the "agreed fact" is written implies that we received tickets and then our hotel voucher. "

I do not think it implies that

you also said

" Therefore, reason one for our delayed bags was the change of PNR. "

The reason for the change of PNR was the missed connection, which is the agreed fact.

you then go on to say

Reason three, no one at BA was willing to book our bags on a later flight, when we contacted them by phone, explaining what happened.
My guess is, that the luggage would have sat at Heathrow indefinitely under our old PNR, since according to those records we were still at the airport. And having only 21 days before they declare your luggage lost and then destroying it, we were understandably interested in having BA be active and correct the error.

this shows a lack of understanding of delayed baggage handling

I doubt guesses and assumptions will work well at CEDR. Your bags reached you and I suspect if you had not called they would have reached you at the exact same time. Nobody was every looking for your bags in LHR, no matter how often you phoned or what they told you on the phone.