Also if that is the location of the master, it doesn't matter how old or new it is, still disconnect the bell wire on T3. As you will be opening both sockets you may as well do it at both ends.
To get rid of the dangly filter in the hall, if it is not a master and the master is in the garage, you need an XTF68 or XTF 85, probably the 85, to replace the hall socket. The difference between them is the millimetre dimensions of the box. You will also need a Krone/IDC punchdown tool to connect the wires to the internals. Cheapo ones at similar prices from Maplin, B & Q etc.
You can legally do that. But that can be done when convenient.
Good luck on Monday

My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
Connection - AAISP Home::1 80/20. 200GB. Sync 71097/14070Kbps @ 600m. BQMs - IPv4 & IPv6
Connection - AAISP Home::1 80/20. 200GB. Sync 71097/14070Kbps @ 600m. BQMs - IPv4 & IPv6