They now say the filter pack is available but the spare cable isn't. First actual stock answer in all this faff.

Get separate answers for those two lines, Beth. I'm still chasing a spare cable on another order and the whole-kit wording gives them plenty of room to answer whichever bit is easiest.

Asked for separate dispatch of the available pack and a credit proposal for the cable. They agreed to split the response. No credit amount or collection confirmation yet.

Has maintenance identified the exact spare cable for a parallel local quote?

Yes. Local source quoted the identified cable, and seller has now agreed a credit amount. Purchasing is comparing the difference. Filter pack arrived and stores checked it; cable line remains open.