Poison poo, again.

It is about 8 years since we had our last attack of poison poo and the broad beans curled up and died.  Following clamour from veg growers across the UK (and beyond) Dow chemicals temporarily withdrew the aminopyralids (selective weed killer for grassland) for 2-3 years then reissued it with strict instructions that (hay etc) crops treated with it should not leave the property (even after it has been through a horse).  So all went well for a few years and we started to relax...  Working backwards, our spent mushroom compost supplier said that the product was imported.   We are still investigating the cause.