You want to pick up zinc, magnesium and taking some vitamin b6 with them is good also (this is what ZMA is). Do not get a zinc, magnesium and calcium supplement combo.
Zinc, magnesium need to be taken seperatly from calcium as they compete for the same receptors and reduce absorbsion of the nutrients.
As in the earlier post make sure your essential fatty acid (cod liver or flax oil) is good too.
Oh, im in London btw.