Westsussexlottie,
Beware of certain hop plants - you can pick up ornamental hop plants (Golden Hop) from garden centres, but these won't necessarily give you 'hops'. The hops are the flower of the female hop plant while the male plant produces catkins. The Golden Hop is a lovely plant, with stunning bronzy gold leaves. But it can be disappointing if you are expecting the classic hop flowers. You can take a trip into Kent where the few remaining hop farms normally sell them, and you can be sure of female plants from them (or at least the ones I have bought always been female ones).
Should be able to pick them up March and April.