Because no one answered you I looked up what the RHS say:
When to grow broad beans
In sheltered, southern gardens with well-drained soils, broad beans can be sown directly into the soil in early November or February for harvests as early as May. Sown in November, seeds will germinate within two to four weeks and young plants should overwinter and recommence growth as soon as conditions are favourable in spring. In cold areas, or when winters are severe, plants will need fleece or cloche protection.

Elsewhere, sow beans in pots under cover in February for planting out in spring or direct into the ground in March, April and even early May, for harvests throughout the summer. Pot-raised plants are especially useful where soils are wet or rich in clay (as these soils can lead to seeds rotting in the ground).
hope this helps