I endorse that. Having tried 4 sources of horse manure containing Aminopyralid Herbicide, I called my local council refuse dept and they gave me the number of a private company contracted to process their green waste. I ordered a small tipper load for which I paid £100.
Its a great product but it would be a good idea to top off with garden compost, manure from a source where you can be sure no herbicides are used or pelleted chicken manure.
Thank you both R&A and Plantmark – helpful tips and I shall contact the Council right away. I remembered Charles recommending this as a source but I think he was concerned that it was treated at temperatures which might kill useful microbes(?)