Best Of

I like the CH2 suggestion and different curve if the rest of the system supports it.  (Not familiar with your boiler)

You could use a wind up electro mechanical timer.  Instead of a thermostat.  They are cheap. Available in 15 minute (max), 30 minute (max) etc flavors.  Wind it up to X number of minutes and done.  Shuts itself off.

Mayhem is everywhere. But we're not doomed to fate. Use the brains and skills we're given, do things right, and look out for others. Be helpful. Flippant responses of "that's not DIY" are not helpful. Instead, explain why something might be difficult for someone without the proper tools or experience. That way, they will either be a more educated customer, or a more educated DIYer.
Wishing everyone a happy and safe New Year.