Is the above still generally true?

I was ticketed LHR-GLA-LCY on NV2R fare according to TA receipt, and original rules / benefits showed SDC. I then had to change to LHR-EDI/GLA-LCY to squeeze an extra office stop in, and new receipt from TA showed fare code as VV2R. I checked that the 1PC hold baggage was there as indication that I hadn't move to NOBAG fare, as I thought bag and SDC travelled together.

At LHR-EDI check-in I asked to move to an earlier flight, and they said SDC was not on ticket. I took original BP to lounge (where conversation was easier) and asked again with same result. Should SDC have stayed there, and could / should I have asked them to find it on original booking and honour it? Or do I need to double check with TA that they have kept it in place?