Yes, it was looking that way from the wiring in your EP2002!
It's a smallish boiler so less likely than some to damage itself by overheating, especially if you don't run it with the boiler thermostat set to max. I doubt you did that, since you didn't have a room thermostat. Little Suprimas don't seem to suffer when (mis)wired this way. Overrun stats were introduced originally only on larger models of some boilers.
You're wasting some energy, because when the boiler goes off the heat exchanger is sitting there slowy heating the atmosphere instead of your house, as are the underfloor pipes etc. With an overrun thermostat connected, the pump would typically run on for a minute or two, with a small boiler. By that time the room stat might have brought the boiler on again anyway, or not, depending... Room stats variously "pulse" on and off. That might sound odd but systems work well like that for donkeys years with no problems.
It needs an extra wire between the boiler and (in your case) your programmer's wiring. So it's tediously commonplace that installers don't bother to run one when doing a cheap replacement boiler job.
It's also common to find the wire's there, but the installer didn't use it (deep sigh emoticon!).
I just remembered you have "S" plan - so if the pump "runs on" there's nowhere for the water to go, when the call for heat is removed (the valve shuts). So without doing something else there's no point connecting overrun. It would have to get more complicated... If it's working, I'd leave it.
