The "North Star" interiors on 185s are still nearly new in my head... it certainly doesn't seem like they need replacement.
Working the units myself I do get passengers that are used to other operators or haven’t travelled believing that they’re brand new trains or occasionally that standard is first class.
What I do wish however is that the DfT provide some funding or allowing spending for a mid-life refurbishment that will see the flat cloth seats replaced with a more robust moquette. Similar to what is currently taking place at a Northern.