Some times you learn something new and terribly worrying and today was one of those days. We were watching Utube earlier (a boatbuilding project we are following) when I spotted a Charles Dowdling new video with a broad bean problem. Do try to see it.
Apparently he had put farmyard manure on his broad bean bed in the autumn as he does with his no dig methods. But even though it was well rotted and had grown a winter crop his bean plants failed in a stunted and twisted way. He has found out it is a weed killer sprayed on a grass (hay and straw crop) which is then used as bedding for horses. The chemical went through the horses but did not break down in the resulting manure heap. The chemical/weed killer then reactivated itself on contact with soil and warmer weather and killed his beans.
I should not have been surprised really as we live among cereal growing fields and daily see all the spraying that happens on these crops.
Moral of this story - work harder on making your own compost! Be wary of buying in stuff to put on your soil.