I have one NTE5c and I got rid of the Mk 4 faceplate that the engineer gave me and put a BT-telephone-socket-only front on instead. I can do this because I have no phone, only dsl. I used a very short BT-plug-to-rj11-plug cable into my modem - like a much much shorter old dial-up modem cable.
All my other NTEs are NTE5a’s and have either
BT-phone-socket (BS6312 431A) fronts or AA (aa.net.uk) DSL-only straight-through faceplates on their fronts. I have some RJ11-RJ45 cables and RJ11-RJ11 cables for them, the former being a (slightly) better fit.