Industry scuttlebutt has it that at least two of the major tartan weavers (D.C. Dalgliesh, and I'm not sure what the other was, maybe Lochcarron) were really messed up by the pandemic, including loss of most of their trained workforce (foreigners on work visas that expired) and seizing up of their looms with corrosion due to lack of maintenance and regular use, which compounded the delay problem (the pandemic itself caused backlogs, and the post-pandemic downtime doubled them).

I don't know at present which tartan mills (of kilt-appropriate quality) are actually reliable for getting a full bolt done (much less a kilt-length). But I figure the pros in here have a handle on which weavers are presently viable.