I am having a real problem with foot and leg cramps, especially at night in bed. I have osteoarthritis and fibromyalgia but am not on medication. Are you able to offer any advice regarding how calcium magnesium and potassium can help?

The cramps are very much to do with magnesium deficiency, which is a feature of fibromyalgia. It's rare for anyone on a Western diet (even a restricted one) to lack calcium, but magnesium is a very common deficiency, even without fibromyalgia in the picture. Your arthritic status suggests that this has been on-going for some time.

I'd suggest a course of Salus Haus magnesium liquid, starting with 2 doses daily for 2 weeks and then going down to one dose daily until the cramps are resolved. I'd also suggest a strict observance of the amount of water you are drinking – plain water, not fizzy or flavoured or in tea/coffee. You need at least 1.5 litres daily and more in this hot weather or when on flights. Without sufficient hydration you will be far more prone to cramps.

You can apply Venagel before going to bed, and again if you wake in the night, but this is just for temporary relief rather than correcting the underlying situation.