Thank you everyone.
Zarjaz, that takes me back a bit.
Thanks to everyone for the trouble they have taken to read, look and answer. I appreciate it.
Having taken the time to look more closely during the photo taking it does look like a poor job. I don't know a whole lot about it and I wasn't present when the installer called. It is good to here that my suspicions that it was not proper ethernet cabling seem vindicated.
In answer to your question yes if I remove front part of the box as you asked the phone does go off. Is that significant?
jaime543 - would it simply be a case of removing the cover from the terminating box and fitting it on the master socket then? Is that the best course of action? How would I attach standard cat5/ethernet cable to the box to provide a feed to the modem?
Thanks for the info regarding the Huawei modem too. MHC.
This is all looking a bit slap-dash and a continuation of the palaver we had get Openreach and BT to sort it all out. They failed to turn up for the initial installation appointment and then cancelled the installation entirely all without bothering to let us know. In addition, they disconnected my adsl 4 weeks before the installation appointment, neglected to warn me and I ended up having to pay my previous and better supplier because I had requested a cease nearer the time.
You have to laugh...apparently.