Other question relates to if a hedge cannot be seen by rest of the garden surely the whole garden cannot be taken into account. I have asked this before but the answer I received was not clear
For height of floor level above ground level enter 0.
The guidance previously provided makes it clear how to assess/measure the area of your garden affected by the hedge.
Judicial Reviews are usually expected within six weeks. You can complain to the LGO but you will have to show maladministration, and go through the councils complaints process first.
You don't explain why the council have 'turned down' your complaint. It would help if you did.