So the second attempt is better.
I used the paint with PVA and water mixed in, it took longer to dry and gave me time to get a base coat on and covered in flock whilst still wet.
Once this was dry I did a second layer of scatter.
I did this by using an eye/ear dropper and applying a PVA/water/washing up liquid over the board and sprinkling the second layer on.
Here you can see the second layer almost done and a corner that shows the initial layer of flock still to get its second coat.
Here is the second layer done.
After this I will add a few bits of sand and grass and then a final sealing layer of PVA/water/washing up liquid.