Peanuts or ground nuts is a vine and the nuts grow under ground in a casing, usually containing up to three peanuts.The vine grows wild in the tropics and needs hot and sunny conditions to produce the peanuts. They are easy to grow(Diana W is right) and will sprout from the peanuts if you buy the UNROASTED in shell ones.In the tropics the shoots are nipped to encourage the vine to spread and grow quickly. The shoots taste like the broad bean shoots(I nip them(BB) to try and avoid black fly infestation), but you need lots as they shrink like spinach when cooked.
I tried growing peanuts and sweet potato here, in the GH, but failed miserably!! The foliage of the sweet potato was lovely though and would look good if trained around a support !! This was a couple of years ago.
I have seen ads. for both plants in plant catalogs so maybe they have produced plants that have been adapted to grow in the UK.