I think we might be writing at cross purposes. The system you had for your mum obviously worked effectively for you and that is the important thing.

POTS provide(s|d) a fixed point of reference - your address is registered against the number for 999 etc; it provides power for a handset or device; Its been like that for a lot of decades! These are cast iron guarantees. A POTS line has guarantees, enshrined in UK law, that mobile etc does not have. POTS is circuit switched (well it was) which means there is a physical path between the ends for the duration of the conversation.

So, by old school, I mean that you currently have important guarantees about telephony in the UK that will evaporate in future. In 2025 or so, we in the UK will have finished migrating from our old school POTS copper lines and will enjoy our smart new SoGEA lines instead. Single Order Generic Ethernet Access. Instead of an emulated circuit switched line we will use VoIP across the entire country. Nothing wrong with that but it probably won't have the guarantees that POTS had.

Red Care is no more - BT have dropped it on the floor as of Feb this year which may indicate that things are not well with our future comms promises. The general system that Red Care was one product of is still available.

This is the important point: Promises (in law) that we used to be able to rely on for comms may (will) be binned.