increase height of fence

Any fence dividing you and your neighbours are legally only aloud at an optimal hight of 6ft anything higher requires a permit

The legal limit in most areas will be 2 meters or 6ft 6 inches from ground that the fence is built on ,but check with your local council to make sure . With regards to the extra gravel board and the post you will definitely need a longer post in that case as it will come down in strong winds with only a foot in the ground .

as @Cameron_landscapes answered "Neighbours are legally only allowed at an optimal height of 6ft anything higher requires a permit"

According to current regulations, the permissible height for a fence dividing neighbouring properties is typically restricted to 6 feet (or approximately 1.8 meters) without the need for a permit. Any fence exceeding this height limit may require obtaining a permit from the appropriate local authorities or government agency. It is crucial to consult the specific zoning laws and building codes applicable to your jurisdiction to ensure compliance with the legal requirements concerning fence height. These regulations are typically in place to maintain neighbourhood aesthetics, ensure privacy, and address safety concerns. It is advisable to seek guidance from the relevant authorities or a professional, such as a local building inspector or zoning official, to obtain accurate information and ensure compliance with the appropriate regulations regarding fence height.

The legally height restriction of a closed fence is 6ft however in some cases this can be increased. The height restriction applies to the ground level of whoever is installing, you are able to go beyond this hight with an open style trellis as long as it allows light through to next door.