Most of the viable seed present were on plants that had either been missed in the survey and spray earlier in the year, or those that were that vigorous that the spray was struggling to kill them off.
Will look to do another survey in August. So if you are reading this and interested in coming along and helping, you would be more than welcome. For more information please email me and you can be put onto the volunteer database.
Thanks again to everyone for their help, and to Abbie for the photography too!