To add to Gilian's questions:

What substrates do people brumate their coachwhips/racers in??

I have taken Bill's lead and am using 'coir' (coconut fibre).
It seems to have a great texture,remaining moist but not too wet
and allows a passage of air.I heard peat can go stale leading to fungal or microbal growths.But I have allowed my snake a route back into dryer aspen if it requires it whilst brumating.
I notice oak leaf-mould is mentioned as a damp substrate ..interesting!!

I need some advice as this is the first time (brumation) for me
and a worrying time.
regards from the U.K. Paul