As mentioned previously by someone else, I don't believe Walsall (70,000 pop.) has ever had an intercity service (correct me if I'm wrong however)
Corby (around 65,000 pop.) in its 90s or current form has never received a proper intercity service I don't believe. It received regular meridian services for many years between 2008 and 2021 although they were essentially acting as long-distance trains on commuter (or at a push, regional) services. HSTs and Meridians served it to Melton Mowbray (and possibly still do) but I think this is just an extension of the 360 commuter services but using a meridian due to the lack of electrification, and of course those were(/are) extremely irregular. I wouldn't count any of those as a true intercity service, but your opinions may differ.