Hi Swavek, you don't have that many options in easterly winds. The river is great in winter as you don't have any weed.
I would suggest attadale on a NE wind.
goo.gl/maps/oXEpSUtqh6J2 All the darker water is deep so you just need to head towards the deeper spots. There is always a direction in which it's easier to get away from the shore by walking and body dragging with the foil.
Foiling for 15m isn't necessarily great success, you should first focus on riding UPWIND over long distances with the board
touching the water. This will give you more confidence and make further progress on the foil a lot easier
Christian