If you can sew 4 straight lines, a synthetic duvet/quilt is super easy to make.
Pre Brexit, climashield apex would have been top choice insulation, but IIRC clo insulation might do something suitable.
Combine with 2oz/55gsm nylon. (Pertex/skylon type).
Has anyone successfully found a warm camping blanket for sleeping? I don't really like the constriction of sleeping bags, awkward etc.
I've been mulling over just getting an insulated blanket, but a bit worried it might be a bit cold if it gets down to 5 or 6 overnight.