TheScullster used his keyboard to write :
Hi all

One of my not-too-DIY posts - sorry.
I am about to invite quotes for the erection of a fence to 2 sides of my back
garden.
As the site is quite exposed I intend to specify conrete posts.
Q1 - what height of post would be recommended (ie how much post in the
ground)? - The fence will be 1800 high panels on top of 150 high gravel
board.

2 to 3 foot into the ground. The gravel board is a good idea - helps
stop the panels rotting too soon. If the site is very exposed, it might
be worth looking at some measure to prevent the panels being blown out
by the wind - extra battens plus some wire around post and through
panels.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk