Jenny...I had this problem with the street light outside my house, and the only solution to getting it fixed is to keep on reporting it.
Keep a diary and write down exactly when you made each complaint. Follow up these with letters to the Chief Executive. It won't hurt if you contact your local Councillor and get him/her on your side.
Get everybody in the cul-de-sac to report as well !
After a battle that lasted 8 months this year, we were finally rewarded with one of those marvelous new LED lights. I was present when it was installed and it to about 20 mins, thats all !