If there's a problem with the gate or any council maintained fences perhaps try downloading the lovecleanlondon app (if you've got the right kind of phone), take a picture of the problem and log it with them. Lewisham seem very pleased with how they use it to deal with 'quality of life' issues for residents:

http://www.lovecleanlondon.org/Reports/Home

They're milking the PR for starting it off so it might be of some use.