I had a look and couldn't find any discussion on this but I'm sure many have debated the various ideas.

But, when is a Peak a Mountain, and by this I mean when does a subordinate high point to a major mountain get recognition as its own standalone mountain.

There are a few aspects which need to be considered:
* Prominence
* Distance from Parent
* Separation by geographic feature, glacier, col etc

Good examples of Mountains are Maweni which is its own mountain, not a subordinate peak to Kibo, it has a +500m prominence and is some distance from Kibo. Lhotse has a prominence of 600m and a distance of 3km from Everest.
But Annapurna IV has just a 255m prominence to its parent Annapurna.
And in Antarctica, you have Sliverstein Pk which is only 100m lower than Vinson, approx 4km from Vinson but is separated by the substantial Roche Glacier, it is not classified as a Mountain.

I have seen 300m of prominence talked about, but if this were the case many low mountains in places like Scotland would be classified as subordinate peaks and not stand alone mountains.

Thoughts appreciated!

cheers
Andy

You might find this article interesting.

https://www.summitpost.org/is-it-a-peak ... ain/606421

Thanks for that, interesting read. Doesn't quite address my query, but none the less an interesting approach using regression analysis.

Also found this:
The International Climbing and Mountaineering Federation's definition of a peak is that it has a prominence of 30 metres (98 ft) or more; it is a mountain summit if it has a prominence of at least 300 metres (980 ft). Otherwise, it is a subpeak.

yet for the Alps:
for each summit, the level difference between it and the highest adjacent pass or notch should be at least 30 m (calculated as average of the summits at the limit of acceptability). I guess there wouldn't be 82 4000ers if they used the 300m rule!