Now den I have a pergola to build 8 foot above ground with bottoms concreted into soil. If I went in third (4 foot) I'd struggle getting 12 foot 4x4 so thinking of 4x3 wall plate with 3 or 4 foot in ground
Why do you think you need 4 feet in the ground? Do an on-line search and most recommend 1/3 of te height above ground. So. 2.4m (8') above means 800mm (32") below.
All this depth of post is based a on fencing which is subject to high wind loads, have you ever watched the depth of a telegraph pole or street lamp
Could you possibly help me and tell me if this is how a finished fence should look many thanks the post are always wobbley it's a fence a neighbour has had put up but it leads onto my drive and part of garden thankyou for any advice