The british kick out the sout american/spanish settlers of Malvinas. Many of this settlers, were from regions that actually belongs to Argentina

Big mistake here. The 5º Infantry Battalion was conformed by 70% conscrip soldiers. They wasn´t a elite unit (The diferences between others units, it´s that this was prepared for this type of combat)

The Scot Guard Battalion (300 man? Here the Battalion are of 500 man aprox) fight against a part of NACAR company of 5º I. Battalion.
They fight againts two sections of 5º Marines, and 1 section of the RI4 (Army, those tooke parte in goose green battle and retreat to tumbledown). The scotish fight against 100-150 mans.

I wouldn't call that battle including fierce Hand to Hand combat with fixed bayonets a "ran for their lives" also i believe you are underestimating the strenght of 2 Btl SG i'm pretty sure that there were more than 300 men involved in the attack.
IIRC there were two bayonet charges performed by the Scots Guards. When the perimeter was secured by 2 SG the Argies launched a first counter attack which was fought off by the Scots.
The Argies had to withdraw when outflanked by the SG and even then the Argie Marines planned another counter attack, the final withdrawal was ordered by Argies staff back in Stanley.
Btw when the Argie arty started up firing the Mountain top the positions were already taken by the SG so calling it firing at own positions isn't quite correct because at that point the Argie Marines were in retreat and have already left the Mountain top and also is to mention that during the whole battle there was very accurate Mortar fire on the advancing SG by a Argentine Mortar Platoon at Mount William.

Wikipedia quotes 900 Scots versus 500 Marines.