Advice needed on cordless phones plse

[Theresa]

We have an an ancient plug in phone upstairs that doesnt actually ring but you can answer it if you hear the downstairs one ringing (does that make sense?!) and an ancient cordless one downstairs (basic and cheap) that seems to no longer hold a charge so we need some new ones! DH has seen cordless one with multi handsets and thinks that's all we need but i seem to remember a warning with our original cordless one that you should still have a corded one in case there's a power cut as the cordless one wldnt work. I know this is true as sometimes we've switched power socket off by accident and it doesn't work! I suppose we have our mobiles but still like the security of a landline in case there's a problem. Does anyone have any thoughts/advice (or can you not understand what I'm whaffling on about!)
Thanks in advance

We have got these, but you are right ,they have to be pluged into supply to work. I purchased a cheap phone from argos for about 2.50 for emergency use.

Thank you so much! We have borrowed an old corded one from my mum and that's working fine for moment until we get new one. We might just keep hold of the borrowed' one for emergencys!