Sky Fibre Problem Challenge!!

Hi All, Just joined to see if anyone has ever experienced the weird problem I have with my new Sky Fibre Broadband.......

Just went live with fibre broadband today (Upgraded from regular Sky)
As soon as I plugged everything in (filters etc....) the router just kept going through the connection process i.e. Orange flashing face, solid orange face, white face.
The white face only stayed on for about 5 seconds then the process started again!
I then read a post on the net suggesting that it was because the router was plugged into the same "Electrical loop" as the TV! Strange as it sounded I turned the TV off & hey presto the Broadband is solid as a rock.
I've tried plugging the router in upstairs via an extension cable as suggested on the net but to no avail.
As soon as I turn the TV on the Broadband goes into the afore mentioned cycle but if the TV is off there is no problem!!

Any Ideas..........?????

Thanks in advance

Dave