It is great to see large scale open demonstration gardens showing permaculture, explaining the principles and offering a genuine alternative to chemical farming.
Hector is a strong voice against Genetically Modified crops and is making a truly unique contribution to the debate by showing that people of all resources and standing can be actively responsible for their consumption and increase local production of food. This in turns reduces dependence and demand for crops that will withstand months and miles of shipment.
Tapeley demonstrates well the layering of a permaculture garden, in the same way the local forest has many layers. The individual yield for one particular plant may be lower but the combined yield of all the plants is higher.
There can be many layers in the permaculture garden.
http://www.tapeleygardens.com/permaculture.html