Trip meter reset cable

I was trying to sort out my Spada clocks today. They’re going to be mounted into a small twin clock console so I need to remove the trip meter reset cable, which is seized anyway.
I’ve taken the screw out that holds the plastic retainer on to the back of the speedometer, but it doesn’t want to let go. Is there a little trick I’m missing before I resort to brute force?

If the cable is seized there is a good chance the drive end is corroded in the speedo, too much force could damage the odometer so a good splash of oil/freeing agent, a short wait and lots of wriggling should sort it.

Got the cable separated from the speedo. There is a very tiny screw crossways through both the brass ferrule on the end of the cable and the shaft sticking out of the back of the speedo. Couldn’t see it until I cleaned off some of the dirt. The reset itself works fine but the cable has rusted in its installed curve such that it won’t bend/rotate any more.
Doesn’t seem that the cable is available as a separate spare part so I just need to decide whether to try and make something or not bother with the trip. At least I can get the speedo into the console now, and I have a knitting row counter to keep track of refuelling stops.