From looking online, this appears to be a NON-NTE5 faceplate, is that right?

I know I’m not supposed to work on the wires in it, but frankly it’s a bit of a mess as you can see and I’m tempted to replace it with a newer one.
However I’m confused as there seem to be two cables coming into the box from outside – I thought there would only be one. What’s the other one? Could it be an extension? I know ONE of the two white cables is an extension but the other white cable comes through the wall together with the black cable.

It does actually work at the moment, amazingly.

[url=https://flic.kr/p/pRDgXn]IMG_20150113_202335263[/url] by Sandra and Alex, on Flickr

[url=https://flic.kr/p/qvRT3N]IMG_20150113_200023055[/url] by Sandra and Alex, on Flickr

[url=https://flic.kr/p/qL8geU]IMG_20150113_200156545[/url] by Sandra and Alex, on Flickr

Thats an old master socket, if theres another wire coming out of it, it probably goes to an extension socket elsewhere.
TBH you can replace it yourself, as long as you wire it up properly.
Its probably a good idea if you trace the wires back to determine which is the main lead into the building and which is the extension though!

im sure the line in from outside will only use 2 strands, the extentions will use 3?

Thanks – I think one cable (the thicker black one) has 2 wires, and the other (thinner white cable) has 3, so that would make sense that the thicker black one is the main lead.

yip