Creating Visual Block before Planning App

This is a spinoff from Jeremy's privacy thread. What are the best methods of creating a visual block quickly to disarm some potential "overlooking" objections from ground floor windows into neighbouring gardens, if it needs to look permanent by the time Planning is applied for? 1 - The classic would be a hard landscape feature - say a brick wall, or a 2m closeboard fence, which can then be conditioned to remain. Problem: pricey at approximately £40-£70+ per metre run for

Thanks for the comments on this thread, @A_L, @Hecateh, @JSHarris, @PeterStarck, @Temp, @ProDave I agree with most comments. 2m in 3 years is doubtless demanding, though something a little ambitious - say 1.4-1.6m in 4 years - may be achievable. As to how I would do such a boundary, I think I might adapt the traditonal field hedge principle of "dig a ditch, build a bank, plant the hedge on the bank" but with a definite boundary feature as the location of the boundary on t