So I've been having these troubles for over a month now. And it is just steadily getting worse and worse. I've had an engineer round to try and fix my line of which helped for all but a day (My line had been messed with, and installed incorrectly with old hardware, some of that down to myself).
Basically it seems that every time I boot up my PC (or any first time new connection) my router tries to send out a DHCP Renew Request, that does not work. Sometimes accompanied by a "No Ranging Response" error. It will disconnect, and reconnect over a few minutes (first started with only happening once every 2 days, for a minute, to being full blown every day almost with it lasting nearly 10 minutes sometimes).
Personally, I feel this might be my Router giving up. The previous fix was done due to too much power being put through the line, and I feel this might have caused some damage to the Router itself.
I've tried soft, and hard restarting. Resetting. Different power sockets. Using different LAN ports. Different cables. Nothing works.