Can I have some advice please? I am looking to build a patio myself adjoining our new extension. I want to go right up to the fence and I also need to go down about 2 foot to be completely level. This means the patio will be below the fence panels and under the concrete footings of the fence posts. Can I extend the fence posts down and redux new concrete footings or should I buy a new bigger fence post and reset it? Or any other suggestions? Thanks for any help.