Some military charts I have seen have had the 100nm.
Now I don't know if that is based on the airfield QNH.
On a bracing day in the Scottish TMA, I have seen a 3 millibar (hPa) difference between GLA & EDI. So I would be cautious using a QNH out to 100nm.
As for the 25nm, look in the AIP etc showing approach charts. Occasionally they fail to mention it.