I have been asked to be a little more specific about the trial - ie what is being asked for. I wrote this in a reply to the email and include it here in case others are also unclear.
"Specifically for the trials over the next few days, plant/sow at the times shown on this page.
So, for the April trial:
Plant/sow around 20:00 GMT on as many days around the 25th April as possible. For instance, 20:00 GMT today, the 24th, the 25th, 26th, 27th, 28th in approximately equivalent conditions and, if possible, with a root crop, a leaf crop, a flower crop and a seed crop. This is a lot to do and if this is not possible reduce the number of crops and days but please include the 25th ad 26th. Please record germination rate, crop weight on harvest, storage duration and disease susceptibility over the life of the crop.