The point being, it seems it was normal to take some kind of salt compliment in hot climates.
Indeed. One of his clients happens to be a heart specialist. So gave him a ring, seeing as the entire health service system is convinced that's the cause. They, in the health service, can see something is wrong, but don't know what. He's had all the heart tests. Usual stuff, look for the worst possible first, then the next worst and so on, to a point that if its not considered life threatening, punt him out in the street or make him pay private for further treatment.
Anyway. Heart specialist suggests, after listening to the symptoms, either a spasm, which was discounted, or Salt deficiency.
Yet the he's been through the entire nhs without mention of either.
Time will tell, but looks promising so far.