You could get BT to replace it with a newer NTE5A - there are ways to get it done free or you may need to pay. Use that with an inbuilt filer and you can do away with dangly filters as both telephony and XDSL plug into the front. Phone extensions are also wired to the rear of te face plate where a filtered signal is provided.
Your burglar alarm should NOT be plugged in but hard wired and moving to an NTE5A makes that a lot easier to achieve.
M H C
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