The diagram shows some turbines in comparison with familiar objects.  From left to right we have the "Gherkin" (30 St. Mary Axe) in London, which is one of the biggest office buildings in London and 180m tall.  Next, and almost too small to see, is a double-decker bus.  Then there are 7MW and 4MW turbines 189m and 150m tall, which is a plausible range of sizes for the Navitus Bay farm (the maximum height of 205m declared by Eneco in its scoping report is actually taller than any of the turbines in the diagram).  This first group of objects is shown at the correct relative scale as they would appear to an observer on a cliff top 45m above sea-level, 14km away.  You have to stand back from your PC screen a distance of 78 times the height of the Gherkin (measure it on your screen) to see these objects at "life-size"; remember there would be many of them.

For comparison, the "small" turbine on the right is modelled on Eneco's other windfarm off the Dutch coast, the "Prinses Amalia" farm.  There, the turbines are 99m tall, but at a range of 24km.  The diagram shows how the relative scale of the Navitus Bay turbines compares with what has been built on the continent taking both size and distance into account..

Here is an animation showing two turbines of different heights in a real-life setting and at the correct scale.  The smaller turbine is 150m above sea level to the blade tip, and the larger is 205m to the blade tip. 
This spans the expected range of turbine sizes for the Navitus Bay windfarm. 
The turbines are both positioned 14km away from an observer 40m above sea level (e.g. on the cliff-top at Durlston).