Is it a plasma tv?

Yes it's Plasma.
I've just moved the router away and tested it and the Downstream speed was fine. Put the router back where it was and the Downstream speed was fine. This isn't making any sense.

Do you know what the SFI will be doing about his findings with regard to the tv - is he coming back at some point?

If the tv was powered off, i.e. not even on standby, and you were still getting excessive error seconds recorded by the router then whole thing does seem a little odd.

He was going to chat with LG and his bosses about it as the reading from the RF Meter was very high while turned on and no interference while on stand by. I've been checking it and can't get the downstream to drop again, but my SNR Downstream has been set at 12dB but is moving a bit. I'm more confused now than ever. There are no faults at all back to the exchange, but it could be an issue with EE's BB gateway. Will a higher NM (12dB) reduce interference - or doesn't it work like that ?

How do the ES rates differ between TV ON, TV OFF & Standby?

Why could it be an issue with EE's BB gateway? Did eng say that?

A higher NM is more tolerant of noise; hence its name and what is interference but noise?

Perhaps pull the plug on the tele before bedtime tonight, reboot the router and check the stats before you power-on the tele tomorrow. Then we can see what the errors look like without any chance of the tele causing problems.

Don't know about the EE BB gateway causing DSL instability although it could affect throughput I guess...

A 12dB SNRM rather than a 3dB, 6dB or 9dB SNRM will give you a larger buffer (increased margin) against noise interference sufficient to cause the DSL to drop. A 12dB SNRM is basically painting over the problem as we discussed before.

I turned my TV on from stand by and his RF Meter picked up interference from the TV and also back to the extension lead. Turned TV off (back to stand by) and interference stopped.

The Engineer did say that the line is clear and it could be a problem with the Orange/BB gateway.

He also said that Openreach would not do a Lift and Shift unless errors appeared during a test.

He has put it down to a TV interference issue, but I've been trying to prove this is the reason - and just can't seem to prove it.

In reply to a post by Vince730i:

his RF Meter picked up interference from the TV

Yes, but that wasn't what I asked. I'm suggesting that it would be worth while measuring how your router reacts to this TV interference cuz it is the errors that it sees that will affect its performance and ultimate connectivity. This will go some way towards proving what you want to prove and cannot see how to.

Sorry. To check how the router is seeing the errors, do I log in to the router and check it that way?

Yes, the usual router stats as we have been monitoring all along.

Concentrate on how the Error Seconds (ES) increase over Time Connected in the various TV situations.