Well spotted Tris. It happened because I sowed carrots (29th June) and they either germinated poorly in dry soil, or were eaten off by slugs, so I planted psb as though they were not there, 20 inches (50cm) apart. Then quite a few carrots emerged by late July and I left them to grow, but have been removong older, bottom leaves of psb to allow light around the carrot leaves. We shall see what happens, it should be possible to pull the carrots without too much root disturbance of their neighbours.
Yes it has been a bountiful season, I hope the same for you.