Just thought I should post resolution for others.
I received a new router, plugged it in and printers connected no problem at all!
So my best guess is that there was a power surge during our last lot of power cuts and that damaged the router. I have a surge protector on quite a lot of kit now as we have power cuts every time there’s a ‘named’ storm and they have a habit of breaking TVs etc - so I will be putting the router on one.
Thank you to everyone who tried to help.
