A few months ago I changed my BT master socket for a nice looking brass one.

Found out today after doing some random searching on the internet that this is actually illegal and I am in breach of my contract with BT....oops

Like an idiot I threw the old BT one away when I put the brass one on, it was an old one not an NTE5 box.

So my question is, I've found some genuine BT NTE5 boxes on eBay....if I buy one of these and take my brass one off to replace it with the NTE5, will BT know I've done it because I've never had an NTE5, just the old style box.

Hope that makes sense

we don't keep any record of what type of line box is installed at property's. if your gonna bother getting one of ebay make sure its the openreach branded one as this has the new bell wire filter for b/band circuits built into it (queue the numourous responses about the bell wire not needed). but to be frank, if you don't mind having a daft white one on your wall then leave your brass one on, and if you ever have a fault, fit the nte5 and use it for testing purposes.

Yes you do.

That is why there is different CSS codes for them and how CPs are able to place orders for the likes of hardwired to PSTN connections.

Granted, the record might not always be correct if, for example, an engineer has went out for a fault and found it was the socket so updated it but records are kept.

i sit corrected. not had a hardwire to pstn conv'n in a long time, easiest jobs in the world they were.