Can you post a picture of the master socket please? Assuming the router is plugged in there

You'll have to upload an image to a photo sharing website, e.g. https://imgur.com and post a link to it here

I understand from other photo's that I have a BT NTE5 master socket that has the filter built in so am to using another filter. If you check my previous posts you will see that I have tried a number of suggestions already.
Is there a way I can take a photo with my iPhone and send it to you?

I can PM you an email address if you like?

Yes that would be better, thanks.