I am posting this after plantmark wrote the following, yet his post did not appear in forum:
Charles, I can now update my progress to report success this year! You will remember my initial efforts were ruined last year having purchased and applied 12 tons of manure over my garden which was badly contaminated with Amino Pyralid insecticide.
Well, I removed every last shovel full and have replaced it with Green Waste Compost to start this year with and results have been fantastic.
I have been unable to source any reliable animal manures so have been using 100% Green Compost. Every plant has been planted with the addition of a sprinkle of Chicken Manure pellets and Micorrhizal Fungi in the planting holes.
For me, the results with the green compost have been so good that it doesn’t warrant taking the risk with horse manure. Everything I have planted has been successful and I have grown a wide range of crops. We have been overrun with most things I have grown, and I am amazed at how few healthy plants are required of each crop to feed two people.
I also removed the horse manure from my greenhouse and replaced with 6″ of green compost, again supplemented with chicken manure pellets. The tomatoes have overrun my 20′ greenhouse despite not having used any tomato feed. Plants are very healthy and show no signs of deficiency.
I have also used a 6″ mulch of Green Compost on my new flower beds and all of the plants have established with great results in their first year. In total I have used 20 tons on the garden and veg patch.
Thank you again for your help with identifying the problem.