I have read that stress can be a factor. I tried Valium (muscle relaxant) but in older people (over 65) it can cause a ‘paradoxical reaction’ - which means it has the opposite effect - causes cramps.
I used to crave sugar in the afternoon - not eating sugar 8 hours before bed and not drinking alcohol 3 hours before bed helps too.
Always turn your electric blanket off before getting into bed (just warm the foot part).
Massage your calf ankle to knee (hands or a small foam roller).
If you have been taking magnesium as a cure for a long time take that back to half dose (and get your blood levels tested for magnesium and B6).
As for the karate chops (I was sceptical) last night I did my usual routine but forgot the chops. At 4am just the soles of both my feet cramped. A quick few chops on each and the stopped. That still puzzles me, but hey, it worked.
Having been where you are I know how painful these are. Just anticipating them creates anxiety.
I’m finally getting some good sleep. Still testing and trying to get the process as short and simple as possible. Hydration and low sugar is a big one.
I’m trying to treat the cause not the symptom.
This is a caring group. Let us know how you get on.
(I’m in Australia).