Slow Reloading after applying config

Here is my problem though, there seems to be no where to make the system aware of the proxy server. This system is located at a school and the proxy is provided by the education authority so I have no control over it.

I am also unable to do updates as per this post here:

The fix mentioned didn’t work in my instance.

I can only assume that the authority has made a change ( i tried asking but no one knew…), as this system was working fine up till now.

Both nslookup and ping work ok to the outside world. (mirror1 returns 162.253.134.144)

What / Where can i edit to insert the proxy server details?

Regards

Dale